background image

 SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

 OCTAL BUS TRANSCEIVERS

 

 SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

Copyright 

©

 1995, Texas Instruments Incorporated

1

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

Local Bus-Latch Capability

Choice of True or Inverting Logic

Package Options Include Plastic

Small-Outline (DW) Packages and Standard

Plastic (N) 300-mil DIPs

DEVICE

OUTPUT

LOGIC

SN74ALS620A

3 state

Inverting

SN74ALS621A

Open collector

True

SN74ALS623A, SN74AS623

3 state

True

 

description

These octal bus transceivers are designed for asynchronous two-way communication between data buses. The

control-function implementation allows for maximum flexibility in timing.

These devices allow data transmission from the A bus to the B bus or from the B bus to the A bus, depending

upon the logic levels at the output-enable (OEAB and OEBA) inputs.

The output-enable inputs disable the device so that the buses are effectively isolated. The dual-enable

configuration gives the transceivers the capability to store data by simultaneously enabling OEAB and OEBA.

Each output reinforces its input in this transceiver configuration. When both OEAB and OEBA are enabled and

all other data sources to the two sets of bus lines are in the high-impedance state, both sets of bus lines (16 total)

remain at their last states. The 8-bit codes appearing on the two sets of buses are identical for the

SN74ALS621A, SN74ALS623A, and SN74AS623 or complementary for the SN74ALS620A.

The -1 versions of the SN74ALS620A and SN74ALS621A are identical to the standard versions, except that

the recommended maximum I

OL

 is increased to 48 mA in the -1 versions.

The SN74ALS620A, SN74ALS621A, SN74ALS623A, and SN74AS623 are characterized for operation from

0

°

C to 70

°

C.

FUNCTION TABLE

INPUTS

OPERATION

OEBA

OEAB

SN74ALS620A

SN74ALS621A

SN74ALS623A

SN74AS623

L

L

B data to A bus

B data to A bus

H

H

A data to B bus

A data to B bus

H

L

Isolation

Isolation

L

H

B data to A bus,

A data to B bus

B data to A bus,

A data to B bus

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

OEAB

A1

A2

A3

A4

A5

A6

A7

A8

GND

V

CC

OEBA

B1

B2

B3

B4

B5

B6

B7

B8

DW OR N PACKAGE

(TOP VIEW)

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.

background image

SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

OCTAL BUS TRANSCEIVERS

 

SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

2

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

logic symbols

2

EN1

19

EN2

1

OEAB

2

A1

B1

18

OEBA

1

SN74ALS620A

2

EN1

19

EN2

1

OEAB

2

A1

3

A2

B1

18

4

A3

5

A4

6

A5

7

A6

8

A7

9

A8

B2

17

B3

16

B5

14

B4

15

B6

13

B8

11

B7

12

OEBA

1

SN74ALS621A

2

EN1

19

EN2

1

OEAB

2

A1

3

A2

B1

18

4

A3

5

A4

6

A5

7

A6

8

A7

9

A8

B2

17

B3

16

B5

14

B4

15

B6

13

B8

11

B7

12

OEBA

1

SN74ALS623A, SN74AS623

3

A2

B2

17

4

A3

B3

16

5

A4

B4

15

6

A5

B5

14

7

A6

B6

13

8

A7

B7

12

9

A8

B8

11

† These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

background image

 SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

 OCTAL BUS TRANSCEIVERS

 

 SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

3

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

logic diagrams (positive logic)

A1

B1

To Seven Other Transceivers

OEBA

OEAB

19

1

18

2

SN74ALS620A

SN74ALS621A

SN74ALS623A, SN74AS623

A1

B1

OEBA

OEAB

19

1

18

2

To Seven Other Transceivers

A1

B1

To Seven Other Transceivers

OEBA

OEAB

19

1

18

2

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

Supply voltage, V

CC

 

 7 V

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

Input voltage, V

I

: All inputs 

 7 V

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

I/O ports 

 5.5 V

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

Operating free-air temperature range, T

A

: SN74ALS620A, SN74ALS623A 

 0

°

C to 70

°

C

. . . . . . . . . . . . . . . . . 

Storage temperature range 

 – 65

°

C to 150

°

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.

background image

SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

OCTAL BUS TRANSCEIVERS

 

SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

4

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

recommended operating conditions

SN74ALS620A

SN74ALS623A

UNIT

MIN

NOM

MAX

VCC

Supply voltage

4.5

5

5.5

V

VIH

High-level input voltage

2

V

VIL

Low-level input voltage

0.8

V

IOH

High-level output current

– 15

mA

IOL

Low-level output current

24

mA

TA

Operating free-air temperature

0

70

°

C

electrical characteristics over recommended operating free-air temperature range (unless

otherwise noted)

PARAMETER

TEST CONDITIONS

SN74ALS620A

SN74ALS623A

UNIT

MIN

TYP†

MAX

VIK

VCC = 4.5 V,

II = – 18 mA

– 1.2

V

VCC = 4.5 V to 5.5 V,

IOH = – 0.4 mA

VCC  – 2

VOH

VCC = 4 5 V

IOH = – 3 mA

2.4

3.2

V

VCC = 4.5 V

IOH = – 15 mA

2

VOL

VCC = 4 5 V

IOL = 12 mA

0.25

0.4

V

VOL

VCC = 4.5 V

IOL = 24 mA‡

0.35

0.5

V

II

Control inputs

VCC = 5 5 V

VI = 7 V

0.1

mA

II

A or B ports

VCC = 5.5 V

VI = 5.5 V

0.1

mA

IIH

Control inputs

VCC = 5 5 V

VI = 2 7 V

20

µ

A

IIH

A or B ports§

VCC = 5.5 V,

VI = 2.7 V

20

µ

A

IIL

Control inputs

VCC = 5 5 V

VI = 0 4 V

– 0.1

mA

IIL

A or B ports§

VCC = 5.5 V,

VI = 0.4 V

– 0.1

mA

IO¶

VCC = 5.5 V,

VO = 2.25 V

– 30

– 112

mA

Outputs high

24

34

SN74ALS620A

VCC = 5.5 V

Outputs low

31

44

ICC

Outputs disabled

33

47

mA

ICC

Outputs high

32

43

mA

SN74ALS623A

VCC = 5.5 V

Outputs low

39

50

Outputs disabled

42

55

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

°

C.

‡ Applies only to the -1 version and only if VCC is between 4.75 V and 5.25 V

§ For I/O ports, the parameters IIH and IIL include the off-state output current.

¶ The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.

background image

 SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

 OCTAL BUS TRANSCEIVERS

 

 SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

5

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

switching characteristics (see Figure 1)

PARAMETER

FROM

(INPUT)

TO

(OUTPUT)

VCC = 4.5 V to 5.5 V,

CL = 50 pF,

R1 = 500 

,

R2 = 500 

,

TA = MIN to MAX†

UNIT

SN74ALS620A

SN74ALS623A

MIN

MAX

MIN

MAX

tPLH

A

B

2

10

2

13

ns

tPHL

A

B

2

10

3

11

ns

tPLH

B

A

2

10

2

13

ns

tPHL

B

A

2

10

3

11

ns

tPZH

OEBA

A

3

17

5

22

ns

tPZL

OEBA

A

5

25

5

22

ns

tPHZ

OEBA

A

2

12

2

16

ns

tPLZ

OEBA

A

3

18

2

19

ns

tPZH

OEAB

B

3

18

5

22

ns

tPZL

OEAB

B

5

25

5

22

ns

tPHZ

OEAB

B

2

12

2

16

ns

tPLZ

OEAB

B

3

18

2

19

ns

† For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

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

Supply voltage, V

CC

 

 7 V

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

Input voltage, V

I

: All inputs and I/O ports 

 7 V

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

Operating free-air temperature range, T

A

: SN74ALS621A  

0

°

C to 70

°

C

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

Storage temperature range 

 – 65

°

C to 150

°

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.

recommended operating conditions

SN74ALS621A

UNIT

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.5

5

5.5

V

VIH

High-level input voltage

2

V

VIL

Low-level input voltage

0.8

V

VOH

High-level output voltage

5.5

V

IOL

Low level output current

24

mA

IOL

Low-level output current

48§

mA

TA

Operating free-air temperature

0

70

°

C

§ Applies only to the -1 version and only if VCC is between 4.75 V and 5.25 V

background image

SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

OCTAL BUS TRANSCEIVERS

 

SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

6

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

electrical characteristics over recommended operating free-air temperature range (unless

otherwise noted)

PARAMETER

TEST CONDITIONS

SN74ALS621A

UNIT

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

VIK

VCC = 4.5 V,

II = – 18 mA

– 1.5

V

IOH

VCC = 4.5 V,

VOH = 5.5 V

0.1

mA

VOL

VCC = 4 5 V

IOL = 24 mA

0.35

0.5

V

VOL

VCC = 4.5 V

IOL = 48 mA‡

0.35

0.5

V

II

Control inputs

VCC = 5 5 V

VI = 7 V

0.1

mA

II

A or B ports

VCC = 5.5 V

VI = 5.5 V

0.1

mA

IIH

Control inputs

VCC = 5 5 V

VI = 2 7 V

20

µ

A

IIH

A or B ports§

VCC = 5.5 V,

VI = 2.7 V

20

µ

A

IIL

Control inputs

VCC = 5 5 V

VI = 0 4 V

– 0.1

mA

IIL

A or B ports§

VCC = 5.5 V,

VI = 0.4 V

– 0.1

mA

ICC

VCC = 5 5 V

Outputs high

29

40

mA

ICC

VCC = 5.5 V

Outputs low

35

48

mA

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

°

C.

‡ Applies only to the -1 version and only if VCC is between 4.75 V and 5.25 V

§ For I/O ports, the parameters IIH and IIL include the off-state output current.

switching characteristics (see Figure 1)

PARAMETER

FROM

(INPUT)

TO

(OUTPUT)

VCC = 4.5 V to 5.5 V,

CL = 50 pF,

RL = 680 

,

TA = MIN to MAX¶

UNIT

(INPUT)

(OUTPUT)

SN74ALS621A

MIN

MAX

tPLH

A

B

10

33

ns

tPHL

A

B

5

20

ns

tPLH

B

A

10

33

ns

tPHL

B

A

5

20

ns

tPLH

OEBA

A

10

39

ns

tPHL

OEBA

A

12

35

ns

tPLH

OEAB

B

10

39

ns

tPHL

OEAB

B

12

35

ns

¶ For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

background image

 SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

 OCTAL BUS TRANSCEIVERS

 

 SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

7

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

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

Supply voltage, V

CC

 

 7 V

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

Input voltage, V

I

: All inputs 

 7 V

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

I/O ports 

 5.5 V

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

Operating free-air temperature range, T

A

: SN74AS623  

0

°

C to 70

°

C

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

Storage temperature range 

 – 65

°

C to 150

°

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.

recommended operating conditions

SN74AS623

UNIT

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.5

5

5.5

V

VIH

High-level input voltage

2

V

VIL

Low-level input voltage

0.8

V

IOH

High-level output current

– 15

mA

IOL

Low-level output current

64

mA

TA

Operating free-air temperature

0

70

°

C

electrical characteristics over recommended operating free-air temperature range (unless

otherwise noted)

PARAMETER

TEST CONDITIONS

SN74AS623

UNIT

PARAMETER

TEST CONDITIONS

MIN

TYP‡

MAX

UNIT

VIK

VCC = 4.5 V,

II = – 18 mA

– 1.2

V

VCC = 4.5 V to 5.5 V,

IOH = – 2 mA

VCC  – 2

VOH

VCC = 4 5 V

IOH = – 3 mA

2.4

3.2

V

VCC = 4.5 V

IOH = – 15 mA

2

VOL

VCC = 4.5 V,

IOL = 64 mA

0.35

0.55

V

II

Control inputs

VCC = 5 5 V

VI = 7 V

0.1

mA

II

A or B ports

VCC = 5.5 V

VI = 5.5 V

0.1

mA

IIH

Control inputs

VCC = 5 5 V

VI = 2 7 V

20

µ

A

IIH

A or B ports§

VCC = 5.5 V,

VI = 2.7 V

70

µ

A

IIL

Control inputs

VCC = 5 5 V

VI = 0 4 V

– 0.5

mA

IIL

A or B ports§

VCC = 5.5 V,

VI = 0.4 V

– 0.75

mA

IO¶

VCC = 5.5 V,

VO = 2.25 V

– 30

– 150

mA

Outputs high

57

93

ICC

VCC = 5.5 V

Outputs low

16

189

mA

Outputs disabled

71

116

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

°

C.

§ For I/O ports, the parameters IIH and IIL include the off-state output current.

¶ The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.

background image

SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

OCTAL BUS TRANSCEIVERS

 

SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

8

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

switching characteristics (see Figure 1)

PARAMETER

FROM

(INPUT)

TO

(OUTPUT)

VCC = 4.5 V to 5.5 V,

CL = 50 pF,

R1 = 500 

,

R2 = 500 

,

TA = MIN to MAX†

UNIT

SN74AS623

MIN

MAX

tPLH

A

B

1

9

ns

tPHL

A

B

1

8

ns

tPLH

B

A

1

9

ns

tPHL

B

A

1

8.5

ns

tPZH

OEBA

A

2

11

ns

tPZL

OEBA

A

2

10

ns

tPHZ

OEBA

A

1

7.5

ns

tPLZ

OEBA

A

1

11.5

ns

tPZH

OEAB

B

2

11.5

ns

tPZL

OEAB

B

2

11

ns

tPHZ

OEAB

B

1

7

ns

tPLZ

OEAB

B

1

9

ns

† For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.

background image

 SN74ALS620A, SN74ALS621A, SN74ALS623A, SN74AS623

 OCTAL BUS TRANSCEIVERS

 

 SDAS226A – DECEMBER 1982 – REVISED JANUARY 1995

9

POST OFFICE BOX 655303 

 DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

SERIES 54ALS/ 74ALS AND 54AS/ 74AS DEVICES

tPHZ

tPLZ

tPHL

tPLH

0.3 V

tPZL

tPZH

tPLH

tPHL

LOAD CIRCUIT

FOR 3-STATE OUTPUTS

From Output

Under Test

Test 

Point

R1

S1

CL

(see Note A)

7 V

1.3 V

1.3 V

1.3 V

3.5 V

3.5 V

0.3 V

0.3 V

th

tsu

VOLTAGE WAVEFORMS

SETUP AND HOLD TIMES

Timing

Input

Data

Input

1.3 V

1.3 V

3.5 V

3.5 V

0.3 V

0.3 V

High-Level

Pulse

Low-Level

Pulse

tw

VOLTAGE WAVEFORMS

PULSE DURATIONS

Input

Out-of-Phase

Output

(see Note C)

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

3.5 V

3.5 V

0.3 V

0.3 V

VOL

VOH

VOH

VOL

Output

Control

(low-level

enabling)

Waveform 1

S1 Closed

(see Note B)

Waveform 2

S1 Open

(see Note B)

[

0 V

VOH

VOL

[

3.5 V

In-Phase

Output

0.3 V

1.3 V

1.3 V

VOLTAGE WAVEFORMS

PROPAGATION DELAY TIMES

VOLTAGE WAVEFORMS

ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS

R2

VCC

RL

Test 

Point

From Output

Under Test

CL

(see Note A)

LOAD CIRCUIT

FOR OPEN-COLLECTOR OUTPUTS

LOAD CIRCUIT FOR 

BI-STATE

TOTEM-POLE OUTPUTS

From Output

Under Test

Test 

Point

CL

(see Note A)

RL

RL = R1 = R2

NOTES: A. CL includes probe and jig capacitance.

B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.

Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.

C. When measuring propagation delay items of 3-state outputs, switch S1 is open.

D. All input pulses have the following characteristics: PRR 

 1 MHz, tr = tf = 2 ns, duty cycle = 50%.

E. The outputs are measured one at a time with one transition per measurement.

Figure 1. Load Circuits and Voltage Waveforms

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