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.
A(14:0)
DECODER
MEMORY
ARRAY
SENSE AMPLIFIER
CE
PE
OE
PROGRAMMING
CONTROL
LOGIC
DQ(7:0)
Figure 1. PROM Block Diagram
1
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. AssertingCE 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 CONFIGURATION
PIN NAMES
A(14:0)
CE
OE
PE
DQ(7:0)
Address
Chip Enable
Output Enable
Program Enable
Data Input/Data Output
Table 1. Device Operation Truth Table
1
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
V
SS
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
V
DD
PE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
Notes:
1. “X” is defined as a “don’t care” condition.
2. Device active; outputs disabled.
OE
X
0
1
1
PE
1
1
0
1
CE
1
0
0
0
I/O MODE
Three-state
Data Out
Data In
Three-state
MODE
Standby
Read
Program
Read
2
ABSOLUTE MAXIMUM RATINGS
1
(Referenced to V
SS
)
SYMBOL
V
DD
V
I/O
T
STG
P
D
T
J
Θ
JC
I
I
PARAMETER
DC supply voltage
Voltage on any pin
Storage temperature
Maximum power dissipation
Maximum junction temperature
Thermal resistance, junction-to-case
2
DC input current
LIMITS
-0.3 to 7.0
-0.5 to (V
DD
+ 0.5)
-65 to +150
1.5
+175
3.3
UNITS
V
V
°C
W
°C
°C/W
mA
±
10
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.
2
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
DD
T
C
V
IN
PARAMETER
Positive supply voltage
Case temperature range
DC input voltage
LIMITS
4.5 to 5.5
-55 to +125
0 to V
DD
UNITS
V
°C
V
DC ELECTRICAL CHARACTERISTICS (Pre/Post-Radiation)*
(V
DD
= 5.0V
±
10%; -55°C < T
C
< +125°C)
SYMBOL
V
IH
V
IL
V
OL1
V
OL2
V
OH1
V
OH2
C
IN 1
C
IO 1, 4
I
IN
I
OZ
PARAMETER
High-level input voltage
Low-level input voltage
Low-level output voltage
Low-level output voltage
High-level output voltage
High-level output voltage
Input capacitance
(TTL)
(TTL)
I
OL
= 4.0mA, V
DD
= 4.5V (TTL)
I
OL
= 200µA, V
DD
= 4.5V (CMOS)
I
OH
= -200µA, V
DD
= 4.5V (CMOS)
I
OH
= -2.0mA, V
DD
= 4.5V (TTL)
ƒ
= 1MHz, V
DD
= 5.0V
V
IN
= 0V
ƒ
= 1MHz, V
DD
= 5.0V
V
OUT
= 0V
Input leakage current
Three-state output leakage
current
V
IN
= 0V to V
DD
V
O
= 0V to V
DD
V
DD
= 5.5V
OE = 5.5V
V
DD
= 5.5V, V
O
= V
DD
V
DD
= 5.5V, V
O
= 0V
TTL inputs levels (I
OUT
= 0), V
IL
=
0.2V
V
DD
, PE = 5.5V
CMOS input levels V
IL
= V
SS
+0.25V
CE = V
DD
- 0.25 V
IH
= V
DD
- 0.25V
-5
-10
5
10
µA
µA
V
DD
-0.1
2.4
15
CONDITION
MINIMUM
2.4
0.8
0.4
V
SS
+ 0.10
MAXIMUM
UNIT
V
V
V
V
V
V
pF
Bidirectional I/O capacitance
15
pF
I
OS 2,3
I
DD1
(OP)
5
Short-circuit output current
90
-90
mA
mA
Supply current operating
@25.0MHz (40ns product)
@22.2MHz (45ns product)
Supply current standby
125
117
2
mA
mA
mA
I
DD2
(SB)
post-rad
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.
3
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.
AC CHARACTERISTICS READ CYCLE (Post-Radiation)*
(V
DD
= 5.0V
±
10%; -55°C < T
C
< +125°C)
SYMBOL
t
AVAV 1
t
AVQV
t
AXQX 2
t
GLQX 2
t
GLQV
t
GHQZ
t
ELQX2
t
ELQV
t
EHQZ
PARAMETER
Read cycle time
Read access time
Output hold time
OE-controlled output enable time
OE-controlled access time
OE-controlled output three-state time
CE-controlled output enable time
CE-controlled access time
CE-controlled output three-state 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.
28F256-45
MIN
MAX
45
45
0
0
15
15
0
45
15
28F256-40
MIN
MAX
40
40
0
0
15
15
0
40
15
UNIT
ns
ns
ns
ns
ns
ns
ns
ns
ns
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.
4
t
AVAV
A(14:0)
CE
t
ELQX
t
ELQV
OE
t
GLQV
DQ(7:0)
t
GLQX
t
AVQV
t
AXQX
t
GHQZ
t
AVQV
t
EHQZ
Figure 2. PROM Read Cycle
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
Synchronous Design Technology :Use a global clock ; do not generate clocks internally except when using a DCM/DLL . If there are multiple clock-synchronous inputs, synchronize them to the fastest cloc...
Is there anyone in the forum who does water quality monitoring? I wonder which sensor companies and models are currently used by everyone to monitor pH, turbidity, dissolved oxygen, and residual chlor...
The A51 programmer can burn Atmel's series of single-chip microcomputer chips , with the advantages of stable performance, fast burning speed, and high cost performance. The product performance is int...
The creative award collection activity of NXP wireless MCU KW41Z is in progress. As long as you submit an application solution based on NXP KW41Z chip, you will have the opportunity to win a prize fro...
[font=楷体_GB2312][size=3]Share a video tutorial of LPCXpresso, haha, from the NXP website. [/size][/font][[i] This post was last edited by lixiaohai8211 on 2010-4-20 08:46[/i]]...
A vacuum eutectic furnace is a critical piece of equipment used in the manufacturing and processing of various materials, particularly in the fields of microelectronics and nanotechnology. One of t...[Details]
Is electromagnetic radiation from electric vehicles harmful to the human body? Recently, the issue of electromagnetic radiation from electric vehicles has garnered widespread attention. However, pu...[Details]
Ever since the Tesla fire incident, electric cars, already known for their poor reputation, have been subjected to even more scathing criticism. Despite this, many people are still willing to buy t...[Details]
Multi-touch mobile phone
Multi-touch is a system that can respond to multiple touches on the screen at the same time. Multi-touch phones are divided into capacitive and resistive types. Capaci...[Details]
The structure of an LCD TV primarily consists of the LCD display module, power module, driver module (primarily including the main driver board and tuner board), and keypad module. LCD display modu...[Details]
1. Introduction
Electronic scales are gradually replacing traditional measuring tools like springs and balances in everyday life, such as electronic price computing scales and electronic weigh...[Details]
For healthcare professionals, accurate diagnosis and treatment are crucial for a clear picture of a person's health. However, healthcare professionals often rely on tests at medical facilities, cli...[Details]
With the rapid adoption of smart electric vehicles, automotive chips are evolving from auxiliary control units to the foundation of the entire vehicle's intelligence. Their applications extend from...[Details]
Gross profit margin jumped from 13.6% in the first half of last year to 25.9%, almost doubling year-on-year.
On August 21, RoboSense released its interim performance report, in which the...[Details]
On August 21st, Zhiyuan Robotics revealed at its first partner conference that it expects shipments to reach thousands of units this year and tens of thousands next year. The company hopes to reach...[Details]
On August 22, South Korean media Nate reported on the 20th local time that Samsung Electronics is introducing Hyper Cell technology into its most advanced 2nm process technology, striving to improv...[Details]
According to foreign media reports, Nissan Motor has recently reached a cooperation with US battery technology company LiCAP Technologies to jointly promote the research and development of next-gen...[Details]
introduction
According to the China Fire Statistics Yearbook, electrical fires accounted for more than 30% of fire accidents in the past decade, and the trend is increasing year by year. They ...[Details]
Smartphones have become essential digital devices, and the growing number of smartphone-centric applications is enriching people's lives. As users, they desire a better app experience and a wider r...[Details]
PowiGaN achieves 95% efficiency at both light and full loads, meeting critical operational and safety requirements.
DARWIN, Australia and SAN JOSE, Calif.,
August 22, 2025 – Powe...[Details]
FPGA/CPLD
京公网安备 11010802033920号
EEWORLD
