TTL compatible input and TTL/CMOS compatible output
levels
Three-state data bus
Low operating and standby current
- Operating: 80mA maximum @25MHz
•
Derating: 3mA/MHz
- Standby: 1.5mA maximum (post-rad)
Radiation-hardened process and design; total dose
irradiation testing to MIL-STD-883, Method 1019
-
-
-
-
Total dose: 100Krad to 1Megarad(Si)
LET
TH
(0.25) ~ 57 MeV-cm
2
/mg
SEL Immune >110 MeV-cm
2
/mg
No upsets >70 MeV-cm
2
/mg
PRODUCT DESCRIPTION
The UT28F256QL amorphous silicon ViaLink
TM
PROM is a
high performance, asynchronous, radiation-hardened,
32K x 8 programmable memory device. The UT28F256QL
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 UT28F256QL. The combination of radiation-
hardness, fast access time, and low power consumption make the
UT28F256QL ideal for high speed systems designed for
operation in radiation environments.
-
AC and DC testing at factory
No post program conditioning
Packaging options:
- 28-lead 50-mil center flatpack (0.490 x 0.74)
V
DD
: 5.0 volts
+
10%
Standard Microcircuit Drawing 5962-96891
QML Q & V compliant part
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 UT28F256QL 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 CONFIGURATION
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
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
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
Notes:
1. “X” is defined as a “don’t care” condition.
2. Device active; outputs disabled.
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 6.0
-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
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 , all inputs
except PE
Input Capacitance PE
C
IO 1
I
IN
Bidirectional I/O capacitance
ƒ
= 1MHz, V
DD
= 5.0V
V
OUT
= 0V
V
IN
= 0V to V
DD
, all pins except PE
V
IN
= V
DD
, PE only
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
(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
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
20
15
pF
µA
µA
µA
Input leakage current
+5
132
20
I
OZ
Three-state output leakage
current
-20
I
OS 2,3
I
DD1
(OP)
5
Short-circuit output current
120
-120
mA
mA
Supply current operating
@25.0MHz (40ns product)
@22.2MHz (45ns product)
Supply current standby
80
75
1.5
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. Derates at 3.2mA/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
AVAV1
t
AVQV
t
AXQX2
t
GLQX2
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 200mV 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 UT28F256QL PROM incorporates special design and
layout features which allow operation in high-level radiation
environments. Aeroflex Colorado Springs has developed special
low-temperature processing techniques designed to enhance the
total-dose radiation hardness of both the gate oxide and the field
RADIATION HARDNESS DESIGN SPECIFICATIONS
1
Total Dose
Latchup LET Threshold
Memory Cell LET Threshold
Logic Onset LET
SEU Cross Section
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.
1E6
>110
>100
>57
3.1E-12
2.0E-20
rad(Si)
MeV-cm
2
/mg
MeV-cm
2
/mg
MeV-cm
2
/mg
cm
2
/bit
errors/bit day
Error rate - geosynchronous orbit, Adams 90% worst case environment
Note:
1. The PROM will not latchup during radiation exposure under recommended operating conditions.
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