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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 oC to
+125 oC)
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)
- LETTH(0.25) ~ 100 MeV-cm2/mg
- SEL Immune >128 MeV-cm2/mg
- Saturated Cross Section cm2 per bit, 1.0E-11
- 1.2E-8 errors/device-day, Adams 90% geosynchronous
heavy ion
- Memory cell LET threshold: >128 MeV-cm2/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 VDD: 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 MEMORYARRAY
SENSE AMPLIFIER
PROGRAMMING
CONTROL
LOGIC DQ(7:0)
A(14:0)
CE
PE
OE
Figure 1. PROM Block Diagram