background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

1

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

D

12-Bit-Resolution A/D Converter

D

10-

µ

s Conversion Time Over Operating

Temperature

D

11 Analog Input Channels

D

3 Built-In Self-Test Modes

D

Inherent Sample-and-Hold Function

D

Linearity Error . . .

±

1 LSB Max

D

On-Chip System Clock

D

End-of-Conversion Output

D

Unipolar or Bipolar Output Operation

(Signed Binary With Respect to 1/2 the

Applied Voltage Reference)

D

Programmable MSB or LSB First

D

Programmable Power Down

D

Programmable Output Data Length

D

CMOS Technology

D

Application Report Available

     

description

The TLC2543C and TLC2543I are 12-bit, switched-

capacitor, successive-approximation, analog-to-

digital converters. Each device has three control

inputs [chip select (CS), the input-output clock (I/O

CLOCK), and the address input (DATA INPUT)] and

is designed for communication with the serial port of

a host processor or peripheral through a serial 3-state

output. The device allows high-speed data transfers

from the host.

In addition to the high-speed converter and versatile control capability, the device has an on-chip 14-channel

multiplexer that can select any one of 11 inputs or any one of three internal self-test voltages. The

sample-and-hold function is automatic. At the end of conversion, the end-of-conversion (EOC) output goes high

to indicate that conversion is complete. The converter incorporated in the device features differential

high-impedance reference inputs that facilitate ratiometric conversion, scaling, and isolation of analog circuitry

from logic and supply noise. A switched-capacitor design allows low-error conversion over the full operating

temperature range.

The TLC2543C is characterized for operation from T

A

 = 0

°

C to 70

°

C. The TLC2543I is characterized for

operation from T

A

 =  – 40

°

C to 85

°

C. The TLC2543M is characterized for operation from T

A

 =  – 55

°

C to 125

°

C.

Copyright 

©

 1997, Texas Instruments Incorporated

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

 

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

† Microcontroller Based Data Acquisition Using the TLC2543 12-bit Serial-Out ADC (SLAA012)

1

2

3

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

AIN8

GND

V

CC

EOC

I/O CLOCK

DATA INPUT

DATA OUT

CS

REF +

REF –

AIN10

AIN9

(TOP VIEW)

DB, DW, J, OR N PACKAGE

3

2

1 20 19

9 10 11 12 13

4

5

6

7

8

18

17

16

15

14

I/O CLOCK

DATA INPUT

DATA OUT

CS

AIN3

AIN4

AIN5

AIN6

AIN7

FK OR FN PACKAGE

(TOP VIEW)

AIN1

AIN0

AIN10

REF –

AIN2

EOC

AIN8

GND

AIN9

V

CC

REF +

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

2

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

AVAILABLE OPTIONS

PACKAGE

TA

SMALL OUTLINE

PLASTIC CHIP

CARRIER

PLASTIC CHIP

CARRIER

PLASTIC DIP

PLASTIC DIP

(DB)†

(DW)†

(FK)

(FN)†

(J)

(N)

0

°

C to 70

°

C

TLC2543CDB

TLC2543CDW

TLC2543CFN

TLC2543CN

– 40

°

C to 85

°

C

TLC2543IDW

TLC2543IFN

TLC2543IN

– 55

°

C to 125

°

C

TLC2543MFK

TLC2543MJ

† Available in tape and reel and ordered as the TLC2543CDBLE, TLC2543CDWR, TLC2543IDWR, TLC2543CFNR, or TLC2543IFNR.

functional block diagram

14-Channel

Analog

Multiplexer

Sample-and-

Hold

Function

12-Bit

Analog-to-Digital

Converter

(Switched Capacitors)

Self-Test

Reference

Output

Data

Register

12-to-1 Data

Selector and

Driver

Control Logic

and I/O

Counters

Input Address

Register

4

12

12

4

REF +

REF –

DATA

OUT

DATA

INPUT

I/O CLOCK

CS

3

EOC

17

18

15

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

AIN8

AIN9

AIN10

1

2

3

4

5

6

7

8

9

11

12

14

13

16

19

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

3

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

AIN0 – AIN10

1 – 9,

11, 12

I

Analog input. These 11 analog-signal inputs are internally multiplexed. The driving source impedance should

be less than or equal to 50 

Ω 

for 4.1-MHz I/O CLOCK operation and be

 

capable of slewing the analog input

voltage into a capacitance of 60 pF.

CS

15

I

Chip select. A high-to-low transition on CS resets the internal counters and controls and enables DATA OUT,

DATA INPUT, and I/O CLOCK. A low-to-high transition disables DATA INPUT and I/O CLOCK within a setup

time.

DATA INPUT

17

I

Serial-data input. A 4-bit serial address selects the desired analog input or test voltage to be converted next.

The serial data is presented with the MSB first and is shifted in on the first four rising edges of I/O CLOCK.

After the four address bits are read into the address register, I/O CLOCK clocks the remaining bits in order.

DATA OUT

16

O

The 3-state serial output for the A/D conversion result. DATA OUT is in the high-impedance state when CS

is high and active when CS is low. With a valid CS, DATA OUT is removed from the high-impedance state

and is driven to the logic level corresponding to the MSB/LSB† value of the previous conversion result. The

next falling edge of I/O CLOCK drives DATA OUT to the logic level corresponding to the next MSB / LSB, and

the remaining bits are shifted out in order.

EOC

19

O

End of conversion. EOC goes from a high to a low logic level after the falling edge of the last I/O CLOCK and

remains low until the conversion is complete and the data is ready for transfer.

GND

10

Ground. GND is the ground return terminal for the internal circuitry. Unless otherwise noted, all voltage

measurements are with respect to GND.

I/O CLOCK

18

I

Input /output clock. I/O CLOCK receives the serial input and performs the following four functions:

1. It clocks the eight input data bits into the input data register on the first eight rising edges of I/O CLOCK

with the multiplexer address available after the fourth rising edge.

2. On the fourth falling edge of I/O CLOCK, the analog input voltage on the selected multiplexer input

begins charging the capacitor array and continues to do so until the last falling edge of the I/O

CLOCK.

3. It shifts the 11 remaining bits of the previous conversion data out on DATA OUT. Data changes on

the falling edge of I/O CLOCK.

4. It transfers control of the conversion to the internal state controller on the falling edge of the last

I/O CLOCK.

REF +

14

I

Positive reference voltage The upper reference voltage value (nominally VCC) is applied to REF+. The

maximum input voltage range is determined by the difference between the voltage applied to this terminal and

the voltage applied to the REF – terminal.

REF –

13

I

Negative reference voltage. The lower reference voltage value (nominally ground) is applied to REF –.

VCC

20

Positive supply voltage

† MSB/LSB = Most significant bit /least significant bit

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

4

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

absolute maximum ratings over operating free-air temperature range (unless otherwise

noted)

Supply voltage range, V

CC

 (see Note 1) 

– 0.5 V to 6.5 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Input voltage range, V

I

 (any input) 

– 0.3 V to V

CC

 + 0.3 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Output voltage range, V

O

 

– 0.3 V to V

CC

 + 0.3 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Positive reference voltage, V

ref +

 

V

CC

 + 0.1 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Negative reference voltage, V

ref –

 – 0.1 

V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Peak input current, I

I

 (any input) 

±

20 mA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Peak total input current, I

I

 (all inputs) 

±

30 mA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Operating free-air temperature range, T

A

: TLC2543C 

0

°

C to 70

°

C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

TLC2543I – 40

°

C to 85

°

C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

TLC2543M – 55

°

C to 125

°

C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Storage temperature range, T

stg

  – 65

°

C to 150

°

C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Lead temperature 1,6 mm (1/16 inch) from the case for 10 seconds 

260

°

C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 

† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTE 1: All voltage values are with respect to the GND terminal with REF – and GND wired together (unless otherwise noted).

recommended operating conditions

MIN

NOM

MAX

UNIT

Supply voltage, VCC

4.5

5

5.5

V

Positive reference voltage, Vref + (see Note 2)

VCC

V

Negative reference voltage, Vref – (see Note 2)

0

V

Differential reference voltage, Vref + – Vref – (see Note 2)

2.5

VCC VCC + 0.1

V

Analog input voltage (see Note 2)

0

VCC

V

High-level control input voltage, VIH

VCC = 4.5 V to 5.5 V

2

V

Low-level control input voltage, VIL

VCC = 4.5 V to 5.5 V

0.8

V

Clock frequency at I/O CLOCK

0

4.1

MHz

Setup time, address bits at DATA INPUT before I/O CLOCK

, tsu(A) (see Figure 4)

100

ns

Hold time, address bits after I/O CLOCK

, th(A) (see Figure 4)

0

ns

Hold time, CS low after last I/O CLOCK

, th(CS) (see Figure 5)

0

ns

Setup time, CS low before clocking in first address bit, tsu(CS) (see Note 3 and Figure 5)

1.425

µ

s

Pulse duration, I/O CLOCK high, twH(I/O)

120

ns

Pulse duration, I/O CLOCK low, twL(I/O)

120

ns

Transition time, I/O CLOCK high to low, tt(I/O) (see Note 4 and Figure 6)

1

µ

s

Transition time, DATA INPUT and CS, tt(CS)

10

µ

s

TLC2543C

0

70

Operating free-air temperature, TA

TLC2543I

– 40

85

°

C

TLC2543M

– 55

125

NOTES:

2. Analog input voltages greater than that applied to REF+ convert as all ones (111111111111), while input voltages less than that applied

to REF– convert as all zeros (000000000000).

3. To minimize errors caused by noise at the CS input, the internal circuitry waits for a setup time after CS

 before responding to control

input signals. No attempt should be made to clock in an address until the minimum CS setup time has elapsed.

4. This is the time required for the clock input signal to fall from VIHmin to VILmax or to rise from VILmax to VIHmin. In the vicinity of

normal room temperature, the devices function with input clock transition time as slow as 1 

µ

s for remote data acquisition applications

where the sensor and the A/D converter are placed several feet away from the controlling microprocessor.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

5

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

electrical characteristics over recommended operating free-air temperature range, 

V

CC

 = V

ref+

 = 4.5 V to 5.5 V, f

(I/O CLOCK)

 = 4.1 MHz (unless otherwise noted)

PARAMETER

TEST CONDITIONS

TLC2543C, TLC2543I

UNIT

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

VOH

High level output voltage

VCC = 4.5 V,

IOH = –1.6 mA

2.4

V

VOH

High-level output voltage

VCC = 4.5 V to 5.5 V,

IOH = –20 

µ

A

VCC – 0.1

V

VOL

Low level output voltage

VCC = 4.5 V,

IOL = 1.6 mA

0.4

V

VOL

Low-level output voltage

VCC = 4.5 V to 5.5 V,

IOL = 20 

µ

A

0.1

V

IOZ

High-impedance off-state output

VO = VCC,

CS at VCC

1

2.5

µ

A

IOZ

g

current

VO = 0,

CS at VCC

1

– 2.5

µ

A

IIH

High-level input current

VI = VCC

1

2.5

µ

A

IIL

Low-level input current

VI = 0

1

– 2.5

µ

A

ICC

Operating supply current

CS at 0 V

1

2.5

mA

ICC(PD) Power-down current

For all digital inputs,

VI 

 0.5 V or VI 

 VCC – 0.5 V

4

25

µ

A

Selected channel leakage

Selected channel at VCC, Unselected channel at 0 V

1

Selected channel leakage

current

Selected channel at 0 V, 

Unselected channel at VCC

– 1

µ

A

Maximum static analog 

reference current into REF +

Vref + = VCC,

Vref – = GND

1

2.5

µ

A

Ci

Input

Analog inputs

30

60

pF

Ci

capacitance

Control inputs

5

15

pF

† All typical values are at VCC = 5 V, TA = 25

°

C.

electrical characteristics over recommended operating free-air temperature range, 

V

CC

 = V

ref+

 = 4.5 V to 5.5 V, f

(I/O CLOCK)

 = 4.1 MHz (unless otherwise noted)

PARAMETER

TEST CONDITIONS

TLC2543M

UNIT

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

VOH

High level output voltage

VCC = 4.5 V,

IOH = –1.6 mA

2.4

V

VOH

High-level output voltage

VCC = 4.5 V to 5.5 V,

IOH = –20 

µ

A

VCC – 0.1

V

VOL

Low level output voltage

VCC = 4.5 V,

IOL = 1.6 mA

0.4

V

VOL

Low-level output voltage

VCC = 4.5 V to 5.5 V,

IOL = 20 

µ

A

0.1

V

IOZ

High-impedance off-state output

VO = VCC,

CS at VCC

1

2.5

µ

A

IOZ

g

current

VO = 0,

CS at VCC

1

– 2.5

µ

A

IIH

High-level input current

VI = VCC

1

10

µ

A

IIL

Low-level input current

VI = 0

1

– 10

µ

A

ICC

Operating supply current

CS at 0 V

1

10

mA

ICC(PD) Power-down current

For all digital inputs,

VI 

 0.5 V or VI 

 VCC – 0.5 V

4

25

µ

A

Selected channel leakage

Selected channel at VCC, Unselected channel at 0 V

10

Selected channel leakage

current

Selected channel at 0 V,

Unselected channel at VCC

– 10

µ

A

Maximum static analog

reference current into REF +

Vref + = VCC,

Vref – = GND

1

2.5

µ

A

Ci

Input 

Analog inputs

30

60

pF

Ci

capacitance

Control inputs

5

15

pF

† All typical values are at VCC = 5 V, TA = 25

°

C.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

6

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

operating characteristics over recommended operating free-air temperature range, 

V

CC

 = V

ref+

 = 4.5 V to 5.5 V, f

(I/O CLOCK)

 = 4.1 MHz

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

EL

Linearity error (see Note 5)

See Figure 2

±

1

LSB

ED

Differential linearity error

See Figure 2

±

1

LSB

EO

Offset error (see Note 6)

See Note 2 and 

Figure 2

±

1.5

LSB

EG

Gain error (see Note 6)

See Note 2 and 

Figure 2

±

1

LSB

ET

Total unadjusted error (see Note 7)

±

1.75

LSB

DATA INPUT = 1011

2048

Self-test output code (see Table 3 and Note 8)

DATA INPUT = 1100

0

DATA INPUT = 1101

4095

tconv

Conversion time

See Figures 9 – 14

8

10

µ

s

tc

Total cycle time (access, sample, and conversion)

See Figures 9 – 14

and Note 9

10 + total

I/O CLOCK

periods +

td(I/O-EOC)

µ

s

tacq

Channel acquisition time (sample)

See Figures 9 – 14

and Note 9

4

12

I/O

CLOCK

periods

tv

Valid time, DATA OUT remains valid after I/O CLOCK

See Figure 6

10

ns

td(I/O-DATA)

Delay time, I/O CLOCK

 to DATA OUT valid

See Figure 6

150

ns

td(I/O-EOC)

Delay time, last I/O CLOCK

 to EOC

See Figure 7

1.5

2.2

µ

s

td(EOC-DATA) Delay time, EOC

 to DATA OUT (MSB / LSB)

See Figure 8

100

ns

tPZH, tPZL

Enable time, CS

 to DATA OUT (MSB / LSB driven)

See Figure 3

0.7

1.3

µ

s

tPHZ, tPLZ

Disable time, CS

 to DATA OUT (high impedance)

See Figure 3

70

150

ns

tr(EOC)

Rise time, EOC

See Figure 8

15

50

ns

tf(EOC)

Fall time, EOC

See Figure 7

15

50

ns

tr(bus)

Rise time, data bus

See Figure 6

15

50

ns

tf(bus)

Fall time, data bus

See Figure 6

15

50

ns

td(I/O-CS)

Delay time, last I/O CLOCK

 to CS

 to abort conversion

(see Note 10)

5

µ

s

† All typical values are at TA = 25

°

C.

NOTES:

2. Analog input voltages greater than that applied to REF + convert as all ones (111111111111), while input voltages less than that

applied to REF –  convert as all zeros (000000000000).

5. Linearity error is the maximum deviation from the best straight line through the A/D transfer characteristics.

6. Gain error is the difference between the actual midstep value and the nominal midstep value in the transfer diagram at the specified

gain point after the offset error has been adjusted to zero. Offset error is the difference between the actual midstep value and the

nominal midstep value at the offset point.

7. Total unadjusted error comprises linearity, zero-scale, and full-scale errors.

8. Both the input address and the output codes are expressed in positive logic.

9. I/O CLOCK period = 1 /(I/O CLOCK frequency) (see Figure 7).

10. Any transitions of CS are recognized as valid only when the level is maintained for a setup time. CS must be taken low at 

 5 

µ

s

of the tenth I/O CLOCK falling edge to ensure a conversion is aborted. Between 5 

µ

s and 10 

µ

s, the result is uncertain as to whether

the conversion is aborted or the conversion results are valid.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

7

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

_

+

C2

0.1 

µ

F

C1

10 

µ

F

C3

470 pF

50 

15 V

50 

– 15 V

VI

AIN0 – AIN10

TLC2543

10 

U1

C1

10 

µ

F

C3

470 pF

C2

0.1 

µ

F

LOCATION

U1

C1

C2

C3

DESCRIPTION

OP27

10-

µ

F 35-V tantalum capacitor

0.1-

µ

F ceramic NPO SMD capacitor

470-pF porcelain Hi-Q SMD capacitor

PART NUMBER

                         —

                         —

AVX 12105C104KA105 or equivalent

Johanson 201S420471JG4L or equivalent

 

Figure 1. Analog Input Buffer to Analog Inputs AIN0 – AIN10

EOC

CL = 50 pF

12 k

DATA OUT

Test Point

VCC

RL = 2.18 k

CL = 100 pF

12 k

Test Point

VCC

RL = 2.18 k

Figure 2. Load Circuits

CS

DATA

OUT

2.4 V

0.4 V

90%

10%

tPZH, tPZL

tPHZ, tPLZ

0.8 V

2 V

Figure 3. DATA OUT to Hi-Z Voltage Waveforms

DATA INPUT

th(A)

0.8 V

2 V

I/O CLOCK

Data

Valid

tsu(A)

0.8 V

Figure 4. DATA INPUT and I/O CLOCK

Voltage Waveforms

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

8

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

Last

Clock

CS

0.8 V

2 V

0.8 V

tsu(CS)

0.8 V

I/O CLOCK

th(CS)

NOTE A: To ensure full conversion accuracy, it is recommended that no input signal change

occurs while a conversion is ongoing.

Figure 5. CS and I/O CLOCK Voltage Waveforms

0.4 V

2.4 V

0.4 V

2.4 V

2 V

0.8 V

I/O CLOCK

DATA OUT

tt(I/O)

0.8 V

2 V

tr(bus), tf(bus)

td(I/O-DATA)

tv

tt(I/O)

0.8 V

I/O CLOCK Period

Figure 6. I/O CLOCK and DATA OUT Voltage Waveforms

Last

Clock

0.8 V

2.4 V

0.4 V

tf(EOC)

td(I/O-EOC)

I/O CLOCK

EOC

Figure 7. I/O CLOCK and EOC Voltage Waveforms

0.4 V

2.4 V

EOC

td(EOC-DATA)

Valid MSB

DATA OUT

0.4 V

2.4 V

tr(EOC)

Figure 8. EOC and DATA OUT Voltage Waveforms

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

9

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

ÎÎÎÎÎÎÎ

ÎÎÎÎÎÎÎ

ÎÎÎ

ÎÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

Access Cycle B

Shift in New Multiplexer Address,

Simultaneously Shift Out Previous

Conversion Value

Sample Cycle B

A/D Conversion

Interval

Initialize

Initialize

MSB

LSB

Previous Conversion Data

MSB

LSB

B7

B6

B5

B4

C7

B11

A11

A10

A9

A8

A7

A6

A5

A4

A1

A0

Hi-Z State

1

2

3

4

5

6

7

8

11

12

1

I/O

CLOCK

DATA

OUT

DATA

INPUT

CS

EOC

(see Note A)

B3

B2

B1

B0

ÎÎÎ

ÎÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

Î

Î

Î

Î

Î

Î

ÎÎ

ÎÎ

ÎÎ

ÎÎ

tconv

NOTE  A: To minimize errors caused by noise at CS, the internal circuitry waits for a setup time after CS

 before responding to control input signals.

Therefore, no attempt should be made to clock in an address until the minimum CS setup time has elapsed.

Figure 9. Timing for 12-Clock Transfer Using CS With MSB First

ÎÎÎ

ÎÎÎ

ÎÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎÎ

ÎÎÎ

ÎÎÎ

Access Cycle B

Shift in New Multiplexer Address,

Simultaneously Shift Out Previous

Conversion Value

Sample Cycle B

A/D Conversion

Interval

Initialize

MSB

LSB

Previous Conversion Data

MSB

LSB

B7

B6

B5

B4

C7

B11

A11

A10

A9

A8

A7

A6

A5

A4

A1

A0

Low Level

1

2

3

4

5

6

7

8

11

12

1

I/O

CLOCK

DATA

OUT

DATA

INPUT

CS

EOC

Initialize

(see Note A)

B3

B2

B1

B0

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

tconv

NOTE  A: To minimize errors caused by noise at CS, the internal circuitry waits for a setup time after CS

 before responding to control input signals.

Therefore, no attempt should be made to clock in an address until the minimum CS setup time has elapsed.

Figure 10. Timing for 12-Clock Transfer Not Using CS With MSB First

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

10

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

ÎÎÎÎÎ

ÎÎÎÎÎ

ÎÎ

ÎÎ

ÎÎÎ

ÎÎÎ

ÎÎ

ÎÎ

ÎÎÎ

ÎÎÎ

Access Cycle B

Shift in New Multiplexer Address,

Simultaneously Shift Out Previous

Conversion Value

Sample Cycle B

A/D Conversion

Interval

Initialize

MSB

LSB

Previous Conversion Data

MSB

LSB

B7

B6

B5

B4

C7

B7

A7

A6

A5

A4

A3

A2

A1

A0

1

2

3

4

5

6

7

8

1

I/O CLOCK

DATA OUT

DATA INPUT

CS

EOC

Initialize

ÎÎÎÎÎÎ

ÎÎÎÎÎÎ

Hi-Z

(see Note A)

B3

B2

B1

B0

ÎÎ

ÎÎ

Î

Î

Î

Î

Î

Î

ÎÎ

ÎÎ

ÎÎ

ÎÎ

tconv

 

NOTE  A: To minimize errors caused by noise at CS, the internal circuitry waits for a setup time after CS

 before responding to control input signals.

Therefore, no attempt should be made to clock in an address until the minimum CS setup time has elapsed.

Figure 11. Timing for 8-Clock Transfer Using CS With MSB First

ÎÎ

ÎÎ

ÎÎÎ

ÎÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

Access Cycle B

Sample Cycle B

A/D Conversion

Interval

Initialize

MSB

LSB

Previous Conversion Data

MSB

LSB

B7

B6

B5

B4

C7

B7

A7

A6

A5

A4

A3

A2

A1

A0

Low Level

1

2

3

4

5

6

7

8

1

I/O CLOCK

DATA OUT

DATA INPUT

CS

EOC

Initialize

(see Note A)

ÎÎ

ÎÎ

B3

B2

B1

B0

Î

Î

Î

Î

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

tconv

Shift in New Multiplexer Address,

Simultaneously Shift Out Previous

Conversion Value

NOTE  A: To minimize errors caused by noise at CS, the internal circuitry waits for a setup time after CS

 before responding to control input signals.

Therefore, no attempt should be made to clock in an address until the minimum CS setup time has elapsed.

Figure 12. Timing for 8-Clock Transfer Not Using CS With MSB First

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

11

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

ÎÎ

ÎÎ

ÎÎÎ

ÎÎÎ

ÎÎÎ

ÎÎÎ

Î

ÎÎ

ÎÎ

A/D Conversion

Interval

Initialize

MSB

LSB

MSB

LSB

B7

B6

B5

B4

C7

B15

A15

A14

A13

A12

A11

A10

A9

A8

A1

A0

1

2

3

4

5

6

7

8

15

16

1

I/O

CLOCK

DATA

OUT

DATA

INPUT

CS

EOC

Initialize

ÎÎÎÎÎÎÎ

ÎÎÎÎÎÎÎ

Hi-Z State

(see Note A)

B3

B2

B1

B0

Access Cycle B

Sample Cycle B

Previous Conversion Data

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

tconv

Shift in New Multiplexer Address,

Simultaneously Shift Out Previous

Conversion Value

NOTE  A: To minimize errors caused by noise at CS, the internal circuitry waits for a setup time after CS

 before responding to control input signals.

Therefore, no attempt should be made to clock in an address until the minimum CS setup time has elapsed.

Figure 13. Timing for 16-Clock Transfer Using CS With MSB First

Î

Î

ÎÎ

ÎÎ

ÎÎ

ÎÎ

Î

Î

ÎÎÎÎ

ÎÎÎÎ

A/D Conversion

Interval

Initialize

MSB

LSB

MSB

LSB

B7

B6

B5

B4

C7

B15

A15

A14

A13

A12

A11

A10

A9

A8

A1

A0

1

2

3

4

5

6

7

8

15

16

1

I/O

CLOCK

DATA

OUT

DATA

INPUT

CS

EOC

Low Level

(see Note A)

B3

B2

B1

B0

Sample Cycle B

Access Cycle B

Previous Conversion Data

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

ÎÎ

tconv

Shift in New Multiplexer Address,

Simultaneously Shift Out Previous

Conversion Value

NOTE  A: To minimize errors caused by noise at CS, the internal circuitry waits for a setup time after CS

 before responding to control input signals.

Therefore, no attempt should be made to clock in an address until the minimum CS setup time has elapsed.

Figure 14. Timing for 16-Clock Transfer Not Using CS With MSB First

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

12

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

Initially, with chip select (CS) high, I/O CLOCK and DATA INPUT are disabled and DATA OUT is in the

high-impedance state. CS going low begins the conversion sequence by enabling I/O CLOCK and DATA INPUT

and removes DATA OUT from the high-impedance state.

The input data is an 8-bit data stream consisting of a 4-bit analog channel address (D7 – D4), a 2-bit data length

select (D3 – D2), an output MSB or LSB first bit (D1), and a unipolar or bipolar output select bit (D0) that are

applied to DATA INPUT. The I/O CLOCK sequence applied to the I/O CLOCK terminal transfers this data to the

input data register.

During this transfer, the I/O CLOCK sequence also shifts the previous conversion result from the output data

register to DATA OUT. I/O CLOCK receives the input sequence of 8, 12, or 16 clock cycles long depending on

the data-length selection in the input data register. Sampling of the analog input begins on the fourth falling edge

of the input I/O CLOCK sequence and is held after the last falling edge of the I/O CLOCK sequence. The last

falling edge of the I/O CLOCK sequence also takes EOC low and begins the conversion.

converter operation

The operation of the converter is organized as a succession of two distinct cycles: 1) the I/O cycle and 2) the

actual conversion cycle.

I/O cycle

The I/O cycle is defined by the externally provided I/O CLOCK and lasts 8, 12, or 16 clock periods, depending

on the selected output data length.

During the I/O cycle, the following two operations take place simultaneously.

An 8-bit data stream consisting of address and control information is provided to DATA INPUT. This data is

shifted into the device on the rising edge of the first eight I/O CLOCKs. DATA INPUT is ignored after the first

eight clocks during 12- or 16-clock I/O transfers.

The data output, with a length of 8, 12, or 16 bits, is provided serially on DATA OUT. When CS is held low, the

first output data bit occurs on the rising edge of EOC. When CS is negated between conversions, the first output

data bit occurs on the falling edge of CS. This data is the result of the previous conversion period, and after the

first output data bit, each succeeding bit is clocked out on the falling edge of each succeeding I/O CLOCK.

conversion cycle

The conversion cycle is transparent to the user, and it is controlled by an internal clock synchronized to

I/O CLOCK. During the conversion period, the device performs a successive-approximation conversion on the

analog input voltage. The EOC output goes low at the start of the conversion cycle and goes high when

conversion is complete and the output data register is latched. A conversion cycle is started only after the I/O

cycle is completed, which minimizes the influence of external digital noise on the accuracy of the conversion.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

13

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

power up and initialization

After power up, CS must be taken from high to low to begin an I/O cycle. EOC is initially high, and the input data

register is set to all zeroes. The contents of the output data register are random, and the first conversion result

should be ignored. To initialize during operation, CS is taken high and is then returned low to begin the next I/O

cycle. The first conversion after the device has returned from the power-down state may not read accurately

due to internal device settling.

Table 1. Operational Terminology

Current (N) I/O cycle

The entire I/O CLOCK sequence that transfers address and control data into the data register and clocks

the digital result from the previous conversion from DATA OUT

Current (N) conversion cycle

The conversion cycle starts immediately after the current I/O cycle. The end of the current I/O cycle is the

last clock falling edge in the I/O CLOCK sequence. The current conversion result is loaded into the output

register when conversion is complete.

Current (N) conversion result

The current conversion result is serially shifted out on the next I/O cycle.

Previous (N – 1) conversion cycle

The conversion cycle just prior to the current I/O cycle

Next (N + 1) I/O cycle

The I/O period that follows the current conversion cycle

Example: In the 12-bit mode, the result of the current conversion cycle is a 12-bit serial-data stream clocked out during

the next I/O cycle. The current I/O cycle must be exactly 12 bits long to maintain synchronization, even

when this corrupts the output data from the previous conversion. The current conversion is begun

immediately after the twelfth falling edge of the current I/O cycle.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

14

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

data input

The data input is internally connected to an 8-bit serial-input address and control register. The register defines

the operation of the converter and the output data length. The host provides the data word with the MSB first.

Each data bit is clocked in on the rising edge of the I/O CLOCK sequence (see Table 2 for the data input-register

format).

Table 2. Input-Register Format

INPUT DATA BYTE

FUNCTION SELECT

ADDRESS BITS

L1

L0

LSBF

BIP

FUNCTION SELECT

D7

(MSB)

D6

D5

D4

D3

D2

D1

D0

(LSB)

Select input channel

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

AIN8

AIN9

AIN10

0

0

0

0

0

0

0

0

1

1

1

0

0

0

0

1

1

1

1

0

0

0

0

0

1

1

0

0

1

1

0

0

1

0

1

0

1

0

1

0

1

0

1

0

Select test voltage

(Vref +  – Vref –)/2

 Vref –

 Vref +

1

1

1

0

1

1

1

0

0

1

0

1

Software power down

1

1

1

0

Output data length

8 bits

12 bits

16 bits

0

X†

1

1

0

1

Output data format

MSB first

LSB first (LSBF)

0

1

Unipolar (binary)

0

Bipolar (BIP) 2s complement

1

† X represents a do not care condition.

data input address bits

The four MSBs (D7 – D4) of the data register address one of the 11 input channels, a reference-test voltage,

or the power-down mode. The address bits affect the current conversion, which is the conversion that

immediately follows the current I/O cycle. The reference voltage is nominally equal to V

ref+

 – V

ref –

.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

15

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

data output length

The next two bits (D3 and D2) of the data register select the output data length. The data-length selection is

valid for the current I/O cycle (the cycle in which the data is read). The data-length selection, being valid for the

current I/O cycle, allows device startup without losing I/O synchronization. A data length of 8, 12, or 16 bits can

be selected. Since the converter has 12-bit resolution, a data length of 12 bits is suggested.

With D3 and D2 set to 00 or 10, the device is in the 12-bit data-length mode and the result of the current

conversion is output as a 12-bit serial data stream during the next I/O cycle. The current I/O cycle must be exactly

12 bits long for proper synchronization, even when this means corrupting the output data from a previous

conversion. The current conversion is started immediately after the twelfth falling edge of the current I/O cycle.

With bits D3 and D2 set to 11, the 16-bit data-length mode is selected, which allows convenient communication

with 16-bit serial interfaces. In the 16-bit mode, the result of the current conversion is output as a 16-bit serial

data stream during the next I/O cycle with the four LSBs always reset to 0 (pad bits). The current I/O cycle must

be exactly 16 bits long to maintain synchronization even when this means corrupting the output data from the

previous conversion. The current conversion is started immediately after the sixteenth falling edge of the current

I/O cycle.

With bits D3 and D2 set to 01, the 8-bit data-length mode is selected, which allows fast communication with 8-bit

serial interfaces. In the 8-bit mode, the result of the current conversion is output as an 8-bit serial data stream

during the next I/O cycle. The current I/O cycle must be exactly eight bits long to maintain synchronization, even

when this means corrupting the output data from the previous conversion. The four LSBs of the conversion

result are truncated and discarded. The current conversion is started immediately after the eighth falling edge

of the current I/O cycle.

Since D3 and D2 take effect on the current I/O cycle when the data length is programmed, there can be a conflict

with the previous cycle when the data-word length is changed from one cycle to the next. This may occur when

the data format is selected to be least significant bit first, since at the time the data length change becomes

effective (six rising edges of I/O CLOCK), the previous conversion result has already started shifting out.

In actual operation, when different data lengths are required within an application and the data length is changed

between two conversions, no more than one conversion result can be corrupted and only when it is shifted out

in LSB-first format.

sampling period

During the sampling period, one of the analog inputs is internally connected to the capacitor array of the

converter to store the analog input signal. The converter starts sampling the selected input immediately after

the four address bits have been clocked into the input data register. Sampling starts on the fourth falling edge

of I/O CLOCK. The converter remains in the sampling mode until the eighth, twelfth, or sixteenth falling edge

of the I/O CLOCK depending on the data-length selection. After the EOC delay time from the last I/O CLOCK

falling edge, the EOC output goes low indicating that the sampling period is over and the conversion period has

begun. After EOC goes low, the analog input can be changed without affecting the conversion result. Since the

delay from the falling edge of the last I/O CLOCK to EOC low is fixed, time-varying analog input signals can be

digitized at a fixed rate without introducing systematic harmonic distortion or noise due to timing uncertainty.

After the 8-bit data stream has been clocked in, DATA INPUT should be held at a fixed digital level until EOC

goes high (indicating that the conversion is complete) to maximize the sampling accuracy and minimize the

influence of external digital noise.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

16

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

data register, LSB first

D1 in the input data register (LSB first) controls the direction of the output binary data transfer. When D1 is reset

to 0, the conversion result is shifted out MSB first. When set to 1, the data is shifted out LSB first. Selection of

MSB first or LSB first always affects the next I/O cycle and not the current I/O cycle. When changing from one

data direction to another, the current I/O cycle is never disrupted.

data register, bipolar format

D0 (BIP) in the input data register controls the binary data format used to represent the conversion result. When

D0 is cleared to 0, the conversion result is represented as unipolar (unsigned binary) data. Nominally, the

conversion result of an input voltage equal to V

ref –

 is a code of all zeros (000 . . . 0), the conversion result of

an input voltage equal to V

ref +

 is a code of all ones (111 . . . 1), and the conversion result of (V

ref +

 + V

ref –

) /2

is a code of a one followed by zeros (100 . . . 0).

When D0 is set to 1, the conversion result is represented as bipolar (signed binary) data. Nominally, conversion

of an input voltage equal to V

ref –

 is a code of a one followed by zeros (100 . . . 0), conversion of an input voltage

equal to V

ref +

 is a code of a zero followed by all ones (011 . . . 1), and the conversion of (V

ref +

 + V

ref –

) /2 is a

code of all zeros (000 . . . 0). The MSB is interpreted as the sign bit. The bipolar data format is related to the

unipolar format in that the MSBs are always each other’s complement.

Selection of the unipolar or bipolar format always affects the current conversion cycle, and the result is output

during the next I/O cycle. When changing between unipolar and bipolar formats, the data output during the

current I/O cycle is not affected.

EOC output

The EOC signal indicates the beginning and the end of conversion. In the reset state, EOC is always high. During

the sampling period (beginning after the fourth falling edge of the I/O CLOCK sequence), EOC remains high

until the internal sampling switch of the converter is safely opened. The opening of the sampling switch occurs

after the eighth, twelfth, or sixteenth I/O CLOCK falling edge, depending on the data-length selection in the input

data register. After the EOC signal goes low, the analog input signal can be changed without affecting the

conversion result.

The EOC signal goes high again after the conversion is completed and the conversion result is latched into the

output data register. The rising edge of EOC returns the converter to a reset state and a new I/O cycle begins.

On the rising edge of EOC, the first bit of the current conversion result is on DATA OUT when CS is low. When

CS is negated between conversions, the first bit of the current conversion result occurs at DATA OUT on the

falling edge of CS.

data format and pad bits

D3 and D2 of the input data register determine the number of significant bits in the digital output that represent

the conversion result. The LSB-first bit determines the direction of the data transfer while the BIP bit determines

the arithmetic conversion. The numerical data is always justified toward the MSB in any output format.

The internal conversion result is always 12 bits long. When an 8-bit data transfer is selected, the four LSBs of

the internal result are discarded to provide a faster one-byte transfer. When a 12-bit transfer is used, all bits are

transferred. When a 16-bit transfer is used, four LSB pad bits are always appended to the internal conversion

result. In the LSB-first mode, four leading zeros are output. In the MSB-first mode, the last four bits output are

zeros.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

17

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

data format and pad bits (continued)

When CS is held low continuously, the first data bit of the newly completed conversion occurs on DATA OUT

on the rising edge of EOC. When a new conversion is started after the last falling edge of I/O CLOCK, EOC goes

low and the serial output is forced to a setting of 0 until EOC goes high again.

When CS is negated between conversions, the first data bit occurs on DATA OUT on the falling edge of CS.

On each subsequent falling edge of I/O CLOCK after the first data bit appears, the data is changed to the next

bit in the serial conversion result until the required number of bits has been output.

chip-select input (CS)

CS enables and disables the device. During normal operation, CS should be low. Although the use of CS is not

necessary to synchronize a data transfer, it can be brought high between conversions to coordinate the data

transfer of several devices sharing the same bus.

When CS is brought high, the serial-data output is immediately brought to the high-impedance state, releasing

its output data line to other devices that may share it. After an internally generated debounce time, I/O CLOCK

is inhibited, thus preventing any further change in the internal state.

When CS is subsequently brought low again, the device is reset. CS must be held low for an internal debounce

time before the reset operation takes effect. After CS is debounced low, I/O CLOCK must remain inactive (low)

for a minimum time before a new I/O cycle can start.

CS can interrupt any ongoing data transfer or any ongoing conversion. When CS is debounced low long enough

before the end of the current conversion cycle, the previous conversion result is saved in the internal output

buffer and shifted out during the next I/O cycle.

power-down features

When a binary address of 1110 is clocked into the input data register during the first four I/O CLOCK cycles,

the power-down mode is selected. Power down is activated on the falling edge of the fourth I/O CLOCK pulse.

During power down, all internal circuitry is put in a low-current standby mode. No conversions are performed,

and the internal output buffer keeps the previous conversion cycle data results provided that all digital inputs

are held above V

CC

 – 0.5 V or below 0.5 V. The I/O logic remains active so the current I/O cycle must be

completed even when the power-down mode is selected. Upon power-on reset and before the first I/O cycle,

the converter normally begins in the power-down mode. The device remains in the power-down mode until a

valid input address (other than 1110) is clocked in. Upon completion of that I/O cycle, a normal conversion is

performed with the results being shifted out during the next I/O cycle.

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

18

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

analog input, test, and power-down mode

The 11 analog inputs, three internal voltages, and power-down mode are selected by the input multiplexer

according to the input addresses shown in Tables 2, 3, and 4. The input multiplexer is a break-before-make type

to reduce input-to-input noise rejection resulting from channel switching. Sampling of the analog input starts on

the falling edge of the fourth I/O CLOCK and continues for the remaining I/O CLOCK pulses. The sample is held

on the falling edge of the last I/O CLOCK pulse. The three internal test inputs are applied to the multiplexer, then

sampled and converted in the same manner as the external analog inputs. The first conversion after the device

has returned from the power-down state may not read accurately due to internal device settling.

Table 3. Analog-Channel-Select Address

ANALOG INPUT

SELECTED

VALUE SHIFTED INTO

DATA INPUT

SELECTED

BINARY

HEX

AIN0

0000

0

AIN1

0001

1

AIN2

0010

2

AIN3

0011

3

AIN4

0100

4

AIN5

0101

5

AIN6

0110

6

AIN7

0111

7

AIN8

1000

8

AIN9

1001

9

AIN10

1010

A

Table 4. Test-Mode-Select Address

INTERNAL

SELF-TEST

VOLTAGE

VALUE SHIFTED INTO

DATA INPUT

UNIPOLAR OUTPUT

RESULT (HEX)‡

VOLTAGE

SELECTED†

BINARY

HEX

RESULT (HEX)‡

Vref + – Vref –

2

1011

B

800

Vref –

1100

C

000

Vref +

1101

D

FFF

† Vref+ is the voltage applied to REF+, and Vref– is the voltage applied to REF–.

‡ The output results shown are the ideal values and may vary with the reference stability

and with internal offsets.

Table 5. Power-Down-Select Address

INPUT COMMAND

VALUE SHIFTED INTO

DATA INPUT

RESULT

BINARY

HEX

Power down

1110

E

ICC 

 25

µ

A

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

19

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

converter and analog input

The CMOS threshold detector in the successive-approximation conversion system determines each bit by

examining the charge on a series of binary-weighted capacitors (see Figure 1). In the first phase of the

conversion process, the analog input  is sampled by closing the S

C

 switch and all S

T

 switches simultaneously.

This action charges all the capacitors to the input voltage.

In the next phase of the conversion process, all S

T

 and S

C

 switches are opened and the threshold detector

begins identifying bits by identifying the charge (voltage) on each capacitor relative to the reference (REF –)

voltage. In the switching sequence, 12 capacitors are examined separately until all 12 bits are identified and

the charge-convert sequence is repeated. In the first step of the conversion phase, the threshold detector  looks

at the first capacitor (weight = 4096). Node 4096 of this capacitor is switched to the  REF+ voltage, and the

equivalent nodes of all the other capacitors on the ladder are switched to REF –. When the voltage at the

summing node is greater than the trip point of the threshold detector (approximately 1/2 V

CC

), a bit 0 is placed

in the output register and the 4096-weight capacitor is switched to REF –. When the voltage at the summing node

is less than the trip point of the threshold detector, a bit 1 is placed in the register and this 4096-weight capacitor

remains connected to REF + through the remainder of the successive-approximation process. The process is

repeated for the 2048-weight capacitor, the 1024-weight capacitor, and so forth down the line until all bits are

determined. With each step of the successive-approximation process, the initial charge is redistributed among

the capacitors. The conversion process relies on charge redistribution to determine the bits from MSB to LSB.

reference voltage inputs

The two reference inputs used with the device are the voltages applied to the REF+ and REF– terminals. These

voltage values establish the upper and lower limits of the analog input to produce a full-scale and zero-scale

reading respectively. These voltages and the analog input should not exceed the positive supply or be lower

than ground consistent with the specified absolute maximum ratings. The digital output is at full scale when the

input signal is equal to or higher than REF+ terminal voltage and at zero when the input signal is equal to or lower

than REF– terminal voltage.

SC

Threshold

Detector

Node 4096

REF –

REF+

ST

4096

VI

To Output

Latches

REF –

ST

REF+

REF –

ST

REF+

REF –

ST

REF+

REF –

ST

REF+

REF –

ST

REF+

REF –

ST

REF+

REF –

ST

REF –

ST

1

1

2

4

8

16

1024

2048

Figure 15. Simplified Model of the Successive-Approximation System

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

20

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

APPLICATION INFORMATION

100000000000

011111111111

000000000010

000000000001

000000000000

111111111110

0

0.0024

2.4564

2.4576

2.4588

Digital Output Code

100000000001

111111111101

111111111111

4.9128

4.9140

4.9152

2048

2047

2

1

0

4094

Step

2049

4093

4095

0.0006

VI – Analog Input Voltage – V

VZT = VZS + 1/2 LSB

VZS

See Notes A and B

4.9134

0.0012

VFT = VFS – 1/2 LSB

VFS

VFSnom

NOTES: A. This curve is based on the assumption that Vref+ and Vref – have been adjusted so that the voltage at the transition from digital 0

to 1 (VZT) is 0.0006 V and the transition to full scale (VFT) is 4.9134 V. 1 LSB = 1.2 mV.

B. The full-scale value (VFS) is the step whose nominal midstep value has the highest absolute value. The zero-scale value (VZS) is

the step whose nominal midstep value equals zero.

Figure 16. Ideal Conversion Characteristics

Processor

Control

Circuit

Analog

Inputs

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

AIN8

AIN9

AIN10

I/O CLOCK

CS

DATA INPUT

DATA OUT

EOC

REF+

REF–

GND

TLC2543

To Source

Ground

5-V DC Regulated

1

2

3

4

5

6

7

8

9

11

12

15

18

17

16

19

14

13

10

Figure 17. Serial Interface

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

21

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

APPLICATION INFORMATION

simplified analog input analysis

Using the equivalent circuit in Figure 18, the time required to charge the analog input capacitance from 0 V to

V

S

 within 1/2 LSB can be derived as follows:

The capacitance charging voltage is given by

(1)

where

R

t

 = R

s

 + r

i

V

C

+

V

S

ǒ

1–e

–tc

ń

RtCi

Ǔ

The final voltage to 1/2 LSB is given by

(2)

V

C

 (1/2 LSB) = V

S

 – (V

S

/8192)

Equating equation 1 to equation 2 and solving for time t

c

 gives

(3)

and

t

c

 (1/2 LSB) = R

t

 

×

 C

i

 

×

 ln(8192)

(4)

V

S

*

ǒ

V

S

ń

8192

Ǔ

+

V

S

ǒ

1–e

–tc

ń

RtCi

Ǔ

Therefore, with the values given, the time for the analog input signal to settle is

(5)

t

c

 (1/2 LSB) = (R

s

 + 1 k

×

 60 pF 

×

 ln(8192)

This time must be less than the converter sample time shown in the timing diagrams.

Rs

ri

VS

VC

60 pF Max

1 k

 Max

Driving Source†

TLC2543

Ci

VI

VI = Input Voltage at AIN

VS = External Driving Source Voltage

Rs = Source Resistance

ri = Input Resistance

Ci = Input Capacitance

VC= Capacitance Charging Voltage

† Driving source requirements:

Noise and distortion for the source must be equivalent to the

resolution of the converter.

Rs must be real at the input frequency.

Figure 18. Equivalent Input Circuit Including the Driving Source

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

22

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

MECHANICAL INFORMATION

DB (R-PDSO-G**)    

PLASTIC SMALL-OUTLINE PACKAGE

4040065 / C 10/95

28 PIN SHOWN

Gage Plane

8,20

7,40

0,15 NOM

0,63

1,03

0,25

38

12,90

12,30

28

10,50

24

8,50

Seating Plane

9,90

7,90

30

10,50

9,90

0,38

5,60

5,00

15

0,22

14

A

28

1

20

16

6,50

6,50

14

0,05 MIN

5,90

5,90

DIM

A  MAX

A  MIN

PINS **

2,00 MAX

6,90

7,50

0,65

M

0,15

0

°

– 8

°

0,10

3,30

8

2,70

NOTES: A. All linear dimensions are in millimeters.

B. This drawing is subject to change without notice.

C. Body dimensions do not include mold flash or protrusion not to exceed 0,15.

D. Falls within JEDEC MO-150

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

23

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

MECHANICAL INFORMATION

DW (R-PDSO-G**)   

PLASTIC SMALL-OUTLINE PACKAGE

16 PIN SHOWN

4040000 / B 03/95

Seating Plane

0.400 (10,15)

0.419 (10,65)

0.104 (2,65) MAX

1

0.012 (0,30)

0.004 (0,10)

A

8

16

0.020 (0,51)

0.014 (0,35)

0.293 (7,45)

0.299 (7,59)

9

0.010 (0,25)

0.050 (1,27)

0.016 (0,40)

(15,24)

(15,49)

PINS **

0.010 (0,25) NOM

A  MAX

DIM

A  MIN

Gage Plane

20

0.500

(12,70)

(12,95)

0.510

(10,16)

(10,41)

0.400

0.410

16

0.600

24

0.610

(17,78)

28

0.700

(18,03)

0.710

0.004 (0,10)

M

0.010 (0,25)

0.050 (1,27)

0

°

– 8

°

NOTES: A. All linear dimensions are in inches (millimeters).

B. This drawing is subject to change without notice.

C. Body dimensions do not include mold flash or protrusion not to exceed 0.006 (0,15).

D. Falls within JEDEC MS-013

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

24

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

MECHANICAL INFORMATION

FK (S-CQCC-N**)     

LEADLESS CERAMIC CHIP CARRIER

4040140 / D 10/96

28 TERMINAL SHOWN

B

0.358

(9,09)

MAX

(11,63)

0.560

(14,22)

0.560

0.458

0.858

(21,8)

1.063

(27,0)

(14,22)

A

NO. OF

MIN

MAX

0.358

0.660

0.761

0.458

0.342

(8,69)

MIN

(11,23)

(16,26)

0.640

0.739

0.442

(9,09)

(11,63)

(16,76)

0.962

1.165

(23,83)

0.938

(28,99)

1.141

(24,43)

(29,59)

(19,32)

(18,78)

**

20

28

52

44

68

84

0.020 (0,51)

TERMINALS

0.080 (2,03)

0.064 (1,63)

(7,80)

0.307

(10,31)

0.406

(12,58)

0.495

(12,58)

0.495

(21,6)

0.850

(26,6)

1.047

0.045 (1,14)

0.045 (1,14)

0.035 (0,89)

0.035 (0,89)

0.010 (0,25)

12

13

14

15

16

18

17

11

10

8

9

7

5

4

3

2

0.020 (0,51)

0.010 (0,25)

6

1

28

26

27

19

21

B SQ

A SQ

22

23

24

25

20

0.055 (1,40)

0.045 (1,14)

0.028 (0,71)

0.022 (0,54)

0.050 (1,27)

NOTES: A. All linear dimensions are in inches (millimeters).

B. This drawing is subject to change without notice.

C. This package can be hermetically sealed with a metal lid.

D. The terminals are gold plated.

E. Falls within JEDEC MS-004

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

25

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

MECHANICAL INFORMATION

J (R-GDIP-T**)    

CERAMIC DUAL-IN-LINE PACKAGE

14 PIN SHOWN

20

0.290

(7,87)

0.310

0.975

(24,77)

(23,62)

0.930

(7,37)

0.245

(6,22)

(7,62)

0.300

18

16

14

PINS **

0.290

(7,87)

0.310

0.785

(19,94)

(19,18)

0.755

(7,37)

0.310

(7,87)

(7,37)

0.290

0.755

(19,18)

(19,94)

0.785

0.245

(6,22)

(7,11)

0.280

A

0.300

(7,62)

(6,22)

0.245

A  MIN

A  MAX

B  MAX

B  MIN

C  MIN

C  MAX

DIM

0.310

(7,87)

(7,37)

0.290

(23,10)

0.910

0.300

(7,62)

(6,22)

0.245

Seating Plane

0.014 (0,36)

0.008 (0,20)

4040083/C 08/96

C

8

7

0.020 (0,51) MIN

B

0.070 (1,78)

0.100 (2,54)

0.065 (1,65)

0.045 (1,14)

14

1

0.015 (0,38)

0.023 (0,58)

0.200 (5,08) MAX

0.130 (3,30) MIN

0.100 (2,54)

0

°

– 15

°

NOTES: A. All linear dimensions are in inches (millimeters).

B. This drawing is subject to change without notice.

C. This package can be hermetically sealed with a ceramic lid using glass frit.

D. Index point is provided on cap for terminal identification only on press ceramic glass frit seal only.

E. Falls within MIL-STD-1835 GDIP1-T14, GDIP1-T16, GDIP1-T18, and GDIP1-T20

background image

TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

 

SLAS079D – DECEMBER 1993 – REVISED MAY 1997

26

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

MECHANICAL INFORMATION

N (R-PDIP-T**)   

PLASTIC DUAL-IN-LINE PACKAGE

20

0.975

(24,77)

0.940

(23,88)

18

0.920

0.850

14

0.775

0.745

(19,69)

(18,92)

16

0.775

(19,69)

(18,92)

0.745

A  MIN

DIM

A  MAX

PINS **

0.310 (7,87)

0.290 (7,37)

(23.37)

(21.59)

Seating Plane

0.010 (0,25) NOM

14/18 PIN ONLY

4040049/C 08/95

9

8

0.070 (1,78) MAX

A

0.035 (0,89) MAX

0.020 (0,51) MIN

16

1

0.015 (0,38)

0.021 (0,53)

0.200 (5,08) MAX

0.125 (3,18) MIN

0.240 (6,10)

0.260 (6,60)

M

0.010 (0,25)

0.100 (2,54)

0

°

– 15

°

16 PIN SHOWN

NOTES: A. All linear dimensions are in inches (millimeters).

B. This drawing is subject to change without notice.

C. Falls within JEDEC MS-001 (20 pin package is shorter then MS-001.)

background image

IMPORTANT NOTICE

Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue

any product or service without notice, and advise customers to obtain the latest version of relevant information

to verify, before placing orders, that information being relied on is current and complete. All products are sold

subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those

pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in

accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent

TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily

performed, except those mandated by government requirements.

CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF

DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL

APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR

WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER

CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO

BE FULLY AT THE CUSTOMER’S RISK.

In order to minimize risks associated with the customer’s applications, adequate design and operating

safeguards must be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent

that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other

intellectual property right of TI covering or relating to any combination, machine, or process in which such

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party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.

Copyright 

©

 1998, Texas Instruments Incorporated