The UT54ACS279 and the UT54ACTS279 contain four basic
S-R flip-flop latches. Under conventional operation, the S-R
inputs are normally held high. When the S input is pulsed low,
the Q output will be set high. When R is pulsed low, the Q
output will be reset low. If the S-R inputs are taken low simul-
taneously, the Q output is unpredictable.
The devices are characterized over full military temperature
range of -55 C to +125 C.
FUNCTION TABLE
INPUTS
S
H
L
H
L
R
H
H
L
L
OUTPUT
Q
Q
0
H
L
H
1
PINOUTS
16-Pin DIP
Top View
1R
1S1
1S2
1Q
2R
2S
2Q
V
SS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
4S
4R
4Q
3S2
3S1
3R
3Q
16-Lead Flatpack
Top View
1R
1S1
1S2
1Q
2R
2S
2Q
V
SS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
4S
4R
4Q
3S2
3S1
3R
3Q
LOGIC SYMBOL
(1)
1R
(2)
1S1
(3)
1S2
(5)
2R
(6)
2S
(10)
3R
(11)
3S1
(12)
3S2
(14)
4R
(15)
4S
Note:
1. This configuration is nonstable. It may not persist when the S and R inputs
return to their inactive (high) level.
R
S1
S1
R
S2
R
S3
S3
R
S4
(4)
1Q
(7)
LOGIC DIAGRAM
(LATCHES 1 & 3)
R
R
(LATCHES 2 & 4)
2Q
(9)
3Q
(13)
4Q
S1
S2
Note:
1. Logic symbol in accordance with ANSI/IEEE standard 91-1984 and IEC
Publication 617-12.
Q
S
Q
195
RadHard MSI Logic
UT54ACS279/UT54ACTS279
RADIATION HARDNESS SPECIFICATIONS
1
PARAMETER
Total Dose
SEU Threshold
2
SEL Threshold
Neutron Fluence
LIMIT
1.0E6
80
120
1.0E14
UNITS
rads(Si)
MeV-cm
2
/mg
MeV-cm
2
/mg
n/cm
2
Notes:
1. Logic will not latchup during radiation exposure within the limits defined in the table.
2. Device storage elements are immune to SEU affects.
ABSOLUTE MAXIMUM RATINGS
SYMBOL
V
DD
V
I/O
T
STG
T
J
T
LS
JC
PARAMETER
Supply voltage
Voltage any pin
Storage Temperature range
Maximum junction temperature
Lead temperature (soldering 5 seconds)
Thermal resistance junction to case
DC input current
Maximum power dissipation
LIMIT
-0.3 to 7.0
-.3 to V
DD
+.3
-65 to +150
+175
+300
20
10
1
UNITS
V
V
C
C
C
C/W
mA
W
I
I
P
D
Note:
1. Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only, functional operation of the device
at these or any other conditions beyond limits indicated in the operational sections is not recommended. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
DD
V
IN
T
C
PARAMETER
Supply voltage
Input voltage any pin
Temperature range
LIMIT
4.5 to 5.5
0 to V
DD
-55 to + 125
UNITS
V
V
C
RadHard MSI Logic
196
UT54ACS279/UT54ACTS279
DC ELECTRICAL CHARACTERISTICS
7
(V
DD
= 5.0V 10%; V
SS
= 0V
6
, -55 C < T
C
< +125 C)
SYMBOL
V
IL
PARAMETER
Low-level input voltage
1
ACTS
ACS
High-level input voltage
1
ACTS
ACS
Input leakage current
ACTS/ACS
Low-level output voltage
3
ACTS
ACS
High-level output voltage
3
ACTS
ACS
Short-circuit output current
2 ,4
ACTS/ACS
Output current
10
(Sink)
I
OH
Output current
10
(Source)
P
total
I
DDQ
I
DDQ
Power dissipation
2, 8, 9
Quiescent Supply Current
Quiescent Supply Current Delta
ACTS
V
IN
= V
DD
or V
SS
I
OL
= 12.0mA
I
OL
= 100 A
I
OH
= -12.0mA
I
OH
= -100 A
V
O
= V
DD
and V
SS
V
IN
= V
DD
or V
SS
V
OL
= 0.4V
V
IN
= V
DD
or V
SS
V
OH
= V
DD
- 0.4V
C
L
= 50pF
V
DD
= 5.5V
For input under test
V
IN
= V
DD
- 2.1V
For all other inputs
V
IN
= V
DD
or V
SS
V
DD
= 5.5V
C
IN
C
OUT
Input capacitance
5
Output capacitance
5
= 1MHz @ 0V
= 1MHz @ 0V
15
15
pF
pF
2.1
10
1.6
mW/
MHz
A
mA
-12
mA
.7V
DD
V
DD
- 0.25
-300
12
300
.5V
DD
.7V
DD
-1
1
CONDITION
MIN
MAX
0.8
.3V
DD
UNIT
V
V
IH
V
I
IN
V
OL
A
0.40
0.25
V
V
OH
V
I
OS
I
OL
mA
mA
197
RadHard MSI Logic
UT54ACS279/UT54ACTS279
Notes:
1. Functional tests are conducted in accordance with MIL-STD-883 with the following input test conditions: V
IH
= V
IH
(min) + 20%, - 0%; V
IL
= V
IL
(max) + 0%,
- 50%, as specified herein, for TTL, CMOS, or Schmitt compatible inputs. Devices may be tested using any input voltage within the above specified range, but
are guaranteed to V
IH
(min) and V
IL
(max).
2. Supplied as a design limit but not guaranteed or tested.
3. Per MIL-PRF-38535, for current density 5.0E5 amps/cm
2
, the maximum product of load capacitance (per output buffer) times frequency should not exceed
3,765 pF/MHz.
4. Not more than one output may be shorted at a time for maximum duration of one second.
5. Capacitance measured for initial qualification and when design changes may affect the value. Capacitance is measured between the designated terminal and V
SS
at frequency of 1MHz and a signal amplitude of 50mV rms maximum.
6. Maximum allowable relative shift equals 50mV.
7. All specifications valid for radiation dose 1E6 rads(Si).
8. Power does not include power contribution of any TTL output sink current.
9. Power dissipation specified per switching output.
10. This value is guaranteed based on characterization data, but not tested.
AC ELECTRICAL CHARACTERISTICS
2
(V
DD
= 5.0V 10%; V
SS
= 0V
1
, -55 C < T
C
< +125 C)
SYMBOL
t
PLH
t
PHL
t
PHL
t
W
S to Q
S to Q
R to Q
Minimum pulse width
S low
R low
PARAMETER
MINIMUM
1
1
1
8
MAXIMUM
15
18
17
UNIT
ns
ns
ns
ns
Notes:
1. Maximum allowable relative shift equals 50mV.
2. All specifications valid for radiation dose 1E6 rads(Si).
