FAST CMOS
1-OF-8 DECODER
WITH ENABLE
Integrated Device Technology, Inc.
DESCRIPTION:
The IDT54/74FCT138T/AT/CT are 1-of-8 decoders built
using an advanced dual metal CMOS technology. The IDT54/
74FCT138T/AT/CT accepts three binary weighted inputs (A
0
,
A
1
, A
2
) and, when enabled, provides eight mutually exclusive
active LOW outputs (
O
0
-
O
7
). The IDT54/74FCT138T/AT/CT
features three enable inputs, two active LOW (
E
1
,
E
2
) and one
active HIGH (E
3
). All outputs will be HIGH unless
E
1
and
E
2
are
LOW and E
3
is HIGH. This multiple enable function allows
easy parallel expansion of the device to a 1-of-32 (5 lines to
32 lines) decoder with just four IDT54/74FCT138T/AT/CT
devices and one inverter.
IDT54/74FCT138T/AT/CT
FUNCTIONAL BLOCK DIAGRAM
2570 drw 01
2570 drw 02
2570 drw 03
PIN CONFIGURATIONS
O
6
INDEX
A
2
O
2
A
0
NC
V
CC
LCC
TOP VIEW
3
2
20 19
1
4
5
6
7
8
18
17
16
15
14
9 10 11 12 13
L20-2
E
1
NC
E
2
E
3
O
1
NC
O
3
O
4
A
1
O
0
O
7
O
5
GND
NC
MILITARY AND COMMERCIAL TEMPERATURE RANGES
APRIL 1995
1995 Integrated Device Technology, Inc.
6.3
DSC-4213/5
O
7
O
6
O
5
O
4
O
3
O
2
O
1
O
0
A
2
A
1
A
0
E
1
E
2
E
3
1
GND
A
0
O
0
O
6
V
CC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
DIP/SOIC/QSOP/CERPACK
TOP VIEW
P16-1
D16-1
SO16-1
SO16-7
&
E16-1
A
1
A
2
E
1
E
2
E
3
O
7
O
1
O
2
O
3
O
4
O
5
FEATURES:
Std., A and C speed grades
Low input and output leakage
1
A (max.)
CMOS power levels
True TTL input and output compatibility
V
OH
= 3.3V (typ.)
V
OL
= 0.3V (typ.)
High drive outputs (-15mA I
OH
, 48mA I
OL
)
Meets or exceeds JEDEC standard 18 specifications
Product available in Radiation Tolerant and Radiation
Enhanced versions
Military product compliant to MIL-STD-883, Class B
and DESC listed (dual marked)
Available in DIP, SOIC, QSOP, CERPACK and
LCC packages
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
6.3
2
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
PIN DESCRIPTION
FUNCTION TABLE
2570 tbl 02
ABSOLUTE MAXIMUM RATINGS
(1)
CAPACITANCE
(T
A
= +25
C, f = 1.0MHz)
2570 tbl 01
Symbol
Rating
Commercial
Military
Unit
V
TERM(2)
Terminal Voltage
with Respect to
GND
0.5 to +7.0
0.5 to +7.0
V
V
TERM(3)
Terminal Voltage
with Respect to
GND
0.5 to
V
CC
+0.5
0.5 to
V
CC
+0.5
V
T
A
Operating
Temperature
0 to +70
55 to +125
C
T
BIAS
Temperature
Under Bias
55 to +125
65 to +135
C
T
STG
Storage
Temperature
55 to +125
65 to +150
C
P
T
Power Dissipation
0.5
0.5
W
I
OUT
DC Output
Current
60 to +120 60 to +120 mA
NOTES:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RAT-
INGS 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
above those indicated in the operational sections of this specification is
not implied. Exposure to absolute maximum rating conditions for
extended periods may affect reliability. No terminal voltage may exceed
V
CC
by +0.5V unless otherwise noted.
2. Input and V
CC
terminals only.
3. Outputs and I/O terminals only.
2570 lnk 03
Symbol
Parameter
(1)
Conditions
Typ.
Max. Unit
C
IN
Input
Capacitance
V
IN
= 0V
6
10
pF
C
OUT
Output
Capacitance
V
OUT
= 0V
8
12
pF
2570 lnk 04
NOTE:
1. This parameter is measured at characterization but not tested.
Pin Names
Description
A
0
A
2
Address Inputs
E
1,
E
2
Enable Inputs (Active LOW)
E
3
Enable Input (Active HIGH)
O
0
O
7
Outputs (Active LOW)
Inputs
Outputs
E
E
1
E
E
2
E
3
A
0
A
1
A
2
O
O
0
O
O
1
O
O
2
O
O
3
O
O
4
O
O
5
O
O
6
O
O
7
H
X
X
X
H
X
X
X
L
X
X
X
X
X
X
X
X
X
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
H
H
H
H
L
H
L
H
L
L
H
H
L
L
L
L
L
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
H
H
H
H
L
H
L
H
L
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
6.3
3
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Commercial: T
A
= 0
C to +70
C, V
CC
= 5.0V
5%; Military: T
A
= 55
C to +125
C, V
CC
= 5.0V
10%
2570 tbl 05
NOTES:
1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
CC
= 5.0V, +25
C ambient.
3. Not more than one output should be shorted at one time. Duration of the short circuit test should not exceed one second.
4. The test limit for this parameter is
5
A at T
A
= 55
C.
Symbol
Parameter
Test Conditions
(1)
Min.
Typ.
(2)
Max.
Unit
V
IH
Input HIGH Level
Guaranteed Logic HIGH Level
2.0
--
--
V
V
IL
Input LOW Level
Guaranteed Logic LOW Level
--
--
0.8
V
I
I H
Input HIGH Current
(4)
V
CC
= Max.
V
I
= 2.7V
--
--
1
A
I
I L
Input LOW Current
(4)
V
CC
= Max.
V
I
= 0.5V
--
--
1
A
I
I
Input HIGH Current
(4)
V
CC
= Max., V
I
= V
CC
(Max.)
--
--
1
A
V
IK
Clamp Diode Voltage
V
CC
= Min., I
N
= 18mA
--
0.7
1.2
V
I
OS
Short Circuit Current
V
CC
= Max.
(3)
, V
O
= GND
60
120
225
mA
V
OH
Output HIGH Voltage
V
CC
= Min.
V
IN
= V
IH
or V
IL
I
OH
= 6mA MIL.
I
OH
= 8mA COM'L.
2.4
3.3
--
V
I
OH
= 12mA MIL.
I
OH
= 15mA COM'L.
2.0
3.0
--
V
V
OL
Output LOW Voltage
V
CC
= Min.
V
IN
= V
IH
or V
IL
I
OL
= 32mA MIL.
I
OL
= 48mA COM'L.
--
0.3
0.5
V
V
H
Input Hysteresis
--
--
200
--
mV
I
CC
Quiescent Power Supply Current
V
CC
= Max.
V
IN
= GND or V
CC
--
0.01
1
mA
6.3
4
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
POWER SUPPLY CHARACTERISTICS
NOTES:
1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
CC
= 5.0V, +25
C ambient.
3. Per TTL driven input (V
IN
= 3.4V). All other inputs at V
CC
or GND.
4. This parameter is not directly testable, but is derived for use in Total Power Supply Calculations.
5. Values for these conditions are examples of the I
CC
formula. These limits are guaranteed but not tested.
6. I
C
= I
QUIESCENT
+ I
INPUTS
+ I
DYNAMIC
I
C
= I
CC
+
I
CC
D
H
N
T
+ I
CCD
(f
o
N
o
)
I
CC
= Quiescent Current
I
CC
= Power Supply Current for a TTL High Input (V
IN
= 3.4V)
D
H
= Duty Cycle for TTL Inputs High
N
T
= Number of TTL Inputs at D
H
I
CCD
= Dynamic Current Caused by an Input Transition Pair (HLH or LHL)
f
o
= Output Frequency
N
o
= Number of Outputs at f
o
All currents are in milliamps and all frequencies are in megahertz.
2570 tbl 06
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
NOTES:
2570 tbl 07
1. See test circuit and waveforms.
2. Minimum limits are guaranteed but not tested on Propagation Delays.
Symbol
Parameter
Test Conditions
(1)
Min.
Typ.
(2)
Max.
Unit
I
CC
Quiescent Power Supply Current
TTL Inputs HIGH
V
CC
= Max.
V
IN
= 3.4V
(3)
--
0.5
2.0
mA
I
CCD
Dynamic Power Supply Current
(4)
V
CC
= Max.
Outputs Open
One Bit Toggling
50% Duty Cycle
V
IN
= V
CC
V
IN
= GND
--
0.15
0.3
mA/
MHz
I
C
Total Power Supply Current
(6)
V
CC
= Max.
Outputs Open
Toggle
E
1
,
E
2
or E
3
V
IN
= V
CC
V
IN
= GND
--
1.5
4.0
mA
50% Duty Cycle
fo = 10MHz
One Input and
One Output Toggling
V
IN
= 3.4V
V
IN
= GND
--
1.8
5.0
FCT138T
FCT138AT
FCT138CT
Com'l.
Mil.
Com'l.
Mil.
Com'l.
Mil.
Symbol
Parameter
Condition
(1)
Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max.
Unit
t
PLH
t
PHL
Propagation Delay
A
n
to
O
n
C
L
= 50pF
R
L
= 500
1.5
9.0
1.5 12.0
1.5
5.8
1.5
7.8
1.5
5.1
1.5
6.0
ns
t
PLH
t
PHL
Propagation Delay
E
1
or
E
2
to
O
n
1.5
9.0
1.5 12.5
1.5
5.9
1.5
8.0
1.5
5.2
1.5
6.1
ns
t
PLH
t
PHL
Propagation Delay
E
3
to
O
n
1.5
9.0
1.5 12.5
1.5
5.9
1.5
8.0
1.5
5.2
1.5
6.1
ns
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
6.3
5
TEST CIRCUITS AND WAVEFORMS
TEST CIRCUITS FOR ALL OUTPUTS
ENABLE AND DISABLE TIMES
PROPAGATION DELAY
SWITCH POSITION
Pulse
Generator
R
T
D.U.T.
V
CC
V
IN
C
L
V
OUT
50pF
500
500
7.0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
DATA
INPUT
TIMING
INPUT
ASYNCHRONOUS CONTROL
PRESET
CLEAR
ETC.
SYNCHRONOUS CONTROL
t
SU
t
H
t
REM
t
SU
t
H
HIGH-LOW-HIGH
PULSE
LOW-HIGH-LOW
PULSE
t
W
1.5V
1.5V
SAME PHASE
INPUT TRANSITION
3V
1.5V
0V
1.5V
V
OH
t
PLH
OUTPUT
OPPOSITE PHASE
INPUT TRANSITION
3V
1.5V
0V
t
PLH
t
PHL
t
PHL
V
OL
CONTROL
INPUT
3V
1.5V
0V
3.5V
0V
OUTPUT
NORMALLY
LOW
OUTPUT
NORMALLY
HIGH
SWITCH
CLOSED
SWITCH
OPEN
V
OL
0.3V
0.3V
t
PLZ
t
PZL
t
PZH
t
PHZ
3.5V
0V
1.5V
1.5V
ENABLE
DISABLE
V
OH
PRESET
CLEAR
CLOCK ENABLE
ETC.
SET-UP, HOLD AND RELEASE TIMES
PULSE WIDTH
Test
Switch
Disable Low
Enable Low
Closed
All Other Tests
Open
Open Drain
DEFINITIONS:
C
L
=
Load capacitance: includes jig and probe capacitance.
R
T
=
Termination resistance: should be equal to Z
OUT
of the Pulse
Generator.
2570 tbl 08
2570 drw 04
2570 drw 06
2570 drw 05
2570 drw 08
NOTES:
1. Diagram shown for input Control Enable-LOW and input Control Disable-
HIGH
2. Pulse Generator for All Pulses: Rate
1.0MHz; t
F
2.5ns; t
R
2.5ns
2570 drw 07
6.3
6
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
ORDERING INFORMATION
IDT XX FCT
138T
138AT
138CT
1-of-8 Decoder
54
74
55
C to +125
C
0
C to +70
C
Temp. Range
XXXX
Device Type
X
Package
X
Process
Blank
B
P
D
SO
E
L
Q
Commercial
MIL-STD-883, Class B
Plastic DIP
CERDIP
Small Outline IC
CERPACK
Leadless Chip Carrier
Quarter-size Small Outline Package
X
Family
Blank
High Drive
2570 drw 09
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