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1

Standard Products

 

UT28F256 Radiation-Hardened 32K x 8 PROM

Data Sheet

    

  

December 2002

 

                      

FEATURES

q Programmable, read-only, asynchronous, radiation-

hardened, 32K x 8 memory

-

Supported by industry standard programmer

q 45ns and 40ns maximum address access time (-55 

o

C to 

+125 

o

C)

q TTL compatible input and TTL/CMOS compatible output 

levels

q Three-state data bus

q Low operating and standby current

-

Operating: 125mA maximum @25MHz

 

Derating: 3mA/MHz

-

Standby: 2mA maximum (post-rad)

q Radiation-hardened process and design; total dose     

irradiation testing to MIL-STD-883, Method 1019

-

Total dose:  1E6 rad(Si)

-  LET

TH

(0.25) ~ 100 MeV-cm

2

/mg

     -     SEL Immune >128 MeV-cm

2

/mg

       -   Saturated Cross Section cm

2

 per bit, 1.0E-11

               - 1.2E-8 errors/device-day, Adams 90% geosynchronous   

heavy ion 

-

Memory cell LET threshold: >128 MeV-cm

2

/mg

q QML Q & V compliant part

-

AC and DC testing at factory

q Packaging options: 

-

28-lead 50-mil center flatpack (0.490 x 0.74)

-

28-lead 100-mil center DIP  (0.600 x 1.4) - contact factory

q V

DD

: 5.0 volts 

10%

q  Standard Microcircuit Drawing 5962-96891

PRODUCT DESCRIPTION

The UT28F256 amorphous silicon anti-fuse PROM is a high 

performance, asynchronous, radiation-hardened, 

32K x 8 programmable memory device. The UT28F256 PROM 

features fully asychronous operation requiring no external clocks 

or timing strobes. An advanced radiation-hardened twin-well 

CMOS process technology is used to implement the UT28F256. 

The combination of radiation-hardness, fast access time, and low 

power consumption make the UT28F256 ideal for high speed 

systems designed for operation in radiation environments.

DECODER

MEMORY

ARRAY

SENSE AMPLIFIER

PROGRAMMING

CONTROL

LOGIC

DQ(7:0)

A(14:0)

CE

PE

OE

Figure 1. PROM Block Diagram

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2

DEVICE OPERATION

The UT28F256 has three control inputs: Chip Enable (CE), 

Program Enable (PE), and Output Enable (OE); fifteen address 

inputs, A(14:0); and eight bidirectional data lines, DQ(7:0). CE 

is the device enable input that controls chip selection, active, and 

standby modes. Asserting CE causes I

DD

 to rise to its active value 

and decodes the fifteen address inputs to select one of 32,768 

words in the memory. PE controls program and read operations. 

During a read cycle, OE must be asserted to enable the outputs.

PIN NAMES

Table 1. Device Operation Truth Table 

1

Notes:  

1. “X” is defined as a “don’t care” condition. 

2. Device active; outputs disabled. 

ABSOLUTE MAXIMUM RATINGS 

1

(Referenced to V

SS

)

Notes:

1 . Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only, and  functional operation of the

     device at these or any other conditions beyond limits indicated in the operational sections of this specification is not recommended.  Exposure to

    absolute maximum rating conditions for extended periods may affect device reliability.

2 . Test per MIL-STD-883, Method 1012, infinite heat sink.

A14

A12

A7

A6

A5

A4

A3

A2

A1

A0

DQ0

DQ1

DQ2

V

SS

V

DD

PE

A13

A8

A9

A11

OE

A10

CE

DQ7

DQ6

DQ5

DQ4

DQ3

PIN CONFIGURATION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

A(14:0)

Address

CE

Chip Enable

OE

Output Enable

PE

Program Enable

DQ(7:0)

Data Input/Data Output

OE

PE

CE

I/O MODE

MODE

X

1

1

Three-state

Standby

0

1

0

Data Out

Read

1

0

0

Data In

Program

1

1

0

Three-state

Read 

2

SYMBOL

PARAMETER

LIMITS

UNITS

V

DD

DC supply voltage

-0.3 to 7.0

V

V

I/O

Voltage on any pin

-0.5 to (V

DD 

+ 0.5)

V

T

STG

Storage temperature

-65 to +150

°

C

P

D

Maximum power dissipation

1.5

W

T

J

Maximum junction temperature

+175

°

C

Θ

JC

Thermal resistance, junction-to-case 

2

3.3

°

C/W

I

I

DC input current

±

10

mA

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3

RECOMMENDED OPERATING CONDITIONS

DC ELECTRICAL CHARACTERISTICS (Pre/Post-Radiation)*

(V

DD

 = 5.0V 

±

10%; -55

°

C < T

C

 < +125

°

C)

Notes: 

* Post-radiation performance guaranteed at 25

°

C per MIL-STD-883 Method 1019 at 1E6 rad(Si).

1. Measured only for initial qualification, and after process or design changes that could affect input/output capacitance.

2. Supplied as a design limit but not guaranteed or tested.

3. Not more than one output may be shorted at a time for maximum duration of one second.

4. Functional test.

5. Derates at 3.0mA/MHz.

SYMBOL

PARAMETER

LIMITS

UNITS

V

DD

Positive supply voltage

4.5 to 5.5

V

T

C

Case temperature range

-55 to +125

°

C

V

IN

DC input voltage

0 to V

DD

V

SYMBOL

PARAMETER

CONDITION

MINIMUM

MAXIMUM

UNIT

V

IH

High-level input voltage

(TTL)

2.4

V

V

IL

Low-level input voltage

(TTL)

0.8

V

V

OL1

Low-level output voltage

I

OL

 = 4.0mA, V

DD 

= 4.5V (TTL)

0.4

V

V

OL2

Low-level output voltage

I

OL

 = 200

µ

A, V

DD

 = 4.5V (CMOS)

V

SS 

+ 0.10

V

V

OH1

High-level output voltage

I

OH

 = -200

µ

A, V

DD

 = 4.5V (CMOS)

V

DD

 -0.1

V

V

OH2

High-level output voltage

I

OH

 = -2.0mA, V

DD

 = 4.5V (TTL)

2.4

V

C

IN 

1

Input capacitance 

ƒ

 = 1MHz,  V

DD

 = 5.0V

V

IN 

= 0V

15

pF

C

IO

 1, 4

Bidirectional I/O capacitance 

ƒ

 = 1MHz, V

DD

 = 5.0V

V

OUT

 = 0V

15

pF

I

IN

Input leakage current

V

IN

 = 0V to V

DD

-5

5

µ

A

I

OZ

Three-state output leakage 

current

V

O

 = 0V to V

DD

 

V

DD

 = 5.5V

OE = 5.5V

-10

10

µ

A

I

OS 

2,3

Short-circuit output current 

V

DD

 = 5.5V, V

O

 = V

DD

V

DD

 = 5.5V, V

= 0V

-90

90

mA

mA

I

DD1

(OP)

5

Supply current operating 

@25.0MHz (40ns product)

@22.2MHz (45ns product)

TTL  inputs levels (I

OUT

 = 0), V

IL 

0.2V

V

DD

, PE = 5.5V

125

117

mA

mA

I

DD2

(SB)

post-rad

Supply current standby

CMOS input levels V

IL

 = V

SS

 +0.25V

CE = V

DD 

- 0.25 V

IH

 = V

DD

 - 0.25V

2

mA

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READ CYCLE

A combination of PE greater than V

IH

(min), and CE less than 

V

IL

(max) defines a read cycle. Read access time is measured 

from the latter of device enable, output enable, or valid address 

to valid data output.

An address access read is initiated by a change in address inputs 

while the chip is enabled with OE asserted and PE deasserted. 

Valid data appears on data output, DQ(7:0), after the specified 

t

AVQV

 is satisfied. Outputs remain active throughout the entire 

cycle. As long as device enable and output enable are active, the 

address inputs may change at a rate equal to the minimum read 

cycle time.

The chip enable-controlled access is initiated by CE  going active 

while OE remains asserted, PE remains deasserted, and the 

addresses remain stable for the entire cycle. After the specified 

t

ELQV

 is satisfied, the eight-bit word addressed by A(14:0)  

appears at the data outputs DQ(7:0).

Output enable-controlled access is initiated by OE going active 

while CE is asserted, PE is deasserted, and the addresses are 

stable. Read access time is t

GLQV

 unless t

AVQV

 or t

ELQV

 have 

not been satisfied.

AC CHARACTERISTICS READ CYCLE (Post-Radiation)*

(V

DD

 = 5.0V 

±

10%; -55

°

C < T

C

 < +125

°

C)

Notes: 

*   Post-radiation performance guaranteed at 25

°

C per MIL-STD-883 Method 1019 at 1E6 rads(Si).

1.  Functional test.

2. Three-state is defined as a 400mV change from steady-state output voltage.

SYMBOL

PARAMETER

28F256-45

    MIN           MAX

28F256-40

    MIN           MAX

UNIT

t

AVAV

1

Read cycle time

45

40

ns

t

AVQV

Read access time

45

40

ns

t

AXQX

2

Output hold time

0

0

ns

t

GLQX

2

OE-controlled output enable time 

0

0

ns

t

GLQV

OE-controlled access time

15

15

ns

t

GHQZ

OE-controlled output three-state time

15

15

ns

t

ELQX

2

 

CE -controlled output enable time

0

0

ns

t

ELQV 

CE -controlled access time 

45

40

ns

t

EHQZ

CE-controlled output three-state time 

15

15

ns

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RADIATION HARDNESS

The UT28F256 PROM incorporates special design and layout 

features which allow operation in high-level radiation 

environments. UTMC has developed special low-temperature 

processing techniques designed to enhance the total-dose 

radiation hardness of both the gate oxide and the field oxide while 

maintaining the circuit density and reliability. For transient 

radiation hardness and latchup immunity, UTMC builds all 

radiation-hardened products on epitaxial wafers using an 

advanced twin-tub CMOS process. In addition, UTMC pays 

special attention to power and ground distribution during the 

design phase, minimizing dose-rate upset caused by rail collapse.

RADIATION HARDNESS DESIGN SPECIFICATIONS 

1

Note:

1 . The PROM will not latchup during radiation exposure under recommended operating conditions.

Figure 2. PROM Read Cycle

t

AVAV

t

AVQV

t

ELQV

t

GLQV

t

AVQV

t

AXQX

t

EHQZ

t

GHQZ

A(14:0)

CE

OE

DQ(7:0)

t

GLQX

t

ELQX

Total Dose

1E6

rad(Si)

Latchup LET Threshold 

>128

MeV-cm

2

/mg

Memory Cell LET Threshold

>128

MeV-cm

2

/mg

Transient Upset LET Threshold

54

MeV-cm

2

/mg

Transient Upset Device Cross Section @ LET=128 MeV-cm

2

/mg

1E-6

cm

2

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6

Notes:

1. 50pF including scope probe and test socket.

2. Measurement of data output occurs at the low to high or high to low transition mid-point 

    (TTL input = 1.5V).

90%

Figure 3. AC Test Loads and Input Waveforms

Input 

Pulses

10%

< 5ns

< 5ns

TTL

0V

3.0V

330 ohms

V

REF

=1.73V

50pF

90%

10%

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0.015

0.008

0.015

0.008

PIN NO. 1 ID. 

6

26 PLACES

0.050 BSC

e

E1

0.550 MAX

-B-

7

S1

(4) PLACES

0.000 MIN.

7

-D-

-C-

A

0.115

0.045

0.045

0.026

L

0.370 

0.250

E2

0.180 MIN

E3

0.030 MIN 

E

0.520

0.460

-H-

c

0.009

0.004

0.040

0.022

0.015 28 PLACES

-A-

H

A-B

D

5

S

S

0.010

M

H

A-B

D

5

S

S

M

0.036

TOP VIEW

END VIEW

b

k

k

Q

Figure 5. 28-Lead 50-mil Center Flatpack  (0.490 x 0.74)

Notes:

1.  All exposed metalized areas to be plated per MIL-PRF-38535.

2.  The lid is connected to V

SS

.

3. Lead finishes are in accordance with MIL-PRF-38535.

4. Dimension letters refer to MIL-STD-1835.

5.  Lead position and coplanarity are not measured.

6.  ID mark symbol is vendor option.

7.  With solder, increase maximum by 0.003.

8.  Total weight is approximately 2.4 grams.

D

0.740 MAX

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ORDERING INFORMATION

256K PROM: SMD

Lead Finish:

(A)

=    Solder 

(C) =

Gold

(X)

=

Optional

Case Outline:

(Y)

=

28-pin DIP (contact factory) 

(X)

=

28-lead Flatpack 

Class Designator:

(Q)

=

Class Q

(V)

=

Class V

Device Type

(03) =  45ns Access Time, TTL inputs, CMOS/TTL compatible outputs

(04) =  40ns Access Time, TTL inputs, CMOS/TTL compatible outputs 

 

Drawing Number: 96891

Total Dose:

(F)

=

3E5 rads(Si)

(G)

=

5E5 rads(Si) 

(H)

=

1E6 rads(Si)

(R) =

1E5 rads(Si) 

Federal Stock Class Designator: No options

5962         *   96891  *     *       *     *

Notes:

1. Lead finish (A, C, or X) must  be specified.

2. If an “X” is specified when ordering, part marking will match the lead finish and will be either “A” (solder) or “C” (gold).

3. Total dose radiation must be specified when ordering.  QML Q and QML V not available without radiation hardening.

4. Check factory for availability of 45ns part.

5. Lead finish: Factory programming either solder or gold. Field programming gold only.

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256K PROM

UT   **** 

*

**

 - * *    *   *   *   *

Total Dose:

( )

=

Total dose characteristics neither tested nor guaranteed

Lead Finish: 

(A)

=

Solder 

(C)    =  Gold

(X)

=

Optional

Screening:

(C)

=

Mil Temp

(P)

=

Prototype

 

Package Type:

(P)

=

28-lead DIP (contact factory)

(U)

=

28-lead Flatpack

Access Time:

(40)  =  40ns access time, TTL compatible inputs, CMOS/TTL compatible outputs

(45)  =  45ns access time, TTL compatible inputs, CMOS/TTL compatible outputs

Device Type Modifier:

(T)

=    TTL compatible inputs and CMOS/TTL compatible outputs

Device Type:

(28F256)  =    32Kx8 One Time Programmable PROM

Notes:

1. Lead finish (A,C, or X) must be specified.

2. If an “X” is specified when ordering, then the part marking will match the lead finish and will be either “A” (solder) or “C” (g old).

3. Military Temperature Range flow per UTMC Manufacturing Flows Document. Radiation characteristics are neither tested nor guaranteed and may 

not be specified.

4. Prototype flow per UTMC Manufacturing Flows Document. Devices have prototype assembly and are tested at 25

°

C only. Radiation characteristics 

are neither tested nor guaranteed and may not be specified.

5. Check factory for availability of 45ns part.

6. Lead finish: Factory programming either solder or gold. Field programming gold only.

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10                                                                                                                                                                                                                                      

Notes

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11                                                                                                                                                                                                                                      

Notes