Integrated Device Technology, Inc.
FAST CMOS
1-OF-8 DECODER
WITH ENABLE
DESCRIPTION:
IDT54/74FCT138T/AT/CT
FEATURES:
•
•
•
•
Std., A and C speed grades
Low input and output leakage
≤1µA
(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 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.
FUNCTIONAL BLOCK DIAGRAM
A
2
A
1
A
0
E
1
E
2
E
3
PIN CONFIGURATIONS
A
0
A
1
A
2
E
1
E
2
E
3
O
7
GND
1
2
3
4
5
6
7
8
P16-1
D16-1
SO16-1
SO16-7
&
E16-1
16
15
14
13
12
11
10
9
V
CC
O
0
O
1
O
2
O
3
O
4
O
5
O
6
2570 drw 02
DIP/SOIC/QSOP/CERPACK
TOP VIEW
INDEX
V
CC
NC
1
A
1
A
0
3 2
A
2
O
7
O
6
O
5
O
4
O
3
O
2
O
1
O
0
2570 drw 01
4
5
6
7
8
20 19
18
17
16
15
14
O
0
O
1
O
2
NC
O
3
O
4
E
1
NC
E
2
E
3
L20-2
9 10 11 12 13
GND
NC
O
7
LCC
TOP VIEW
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
MILITARY AND COMMERCIAL TEMPERATURE RANGES
©1995
Integrated Device Technology, Inc.
O
6
O
5
2570 drw 03
APRIL 1995
DSC-4213/5
6.3
1
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
PIN DESCRIPTION
Pin Names
A
0
–A
2
Description
Address Inputs
Enable Inputs (Active LOW)
Enable Input (Active HIGH)
Outputs (Active LOW)
2570 tbl 01
E
1,
E
2
E
3
O
0
–
O
7
FUNCTION TABLE
Inputs
Outputs
A
0
X
X
X
L
H
L
H
L
H
L
H
A
1
X
X
X
L
L
H
H
L
L
H
H
A
2
X
X
X
L
L
L
L
H
H
H
H
E
1
H
X
X
L
L
L
L
L
L
L
L
E
2
X
H
X
L
L
L
L
L
L
L
L
E
3
X
X
L
H
H
H
H
H
H
H
H
O
0
H
H
H
L
H
H
H
H
H
H
H
O
1
H
H
H
H
L
H
H
H
H
H
H
O
2
H
H
H
H
H
L
H
H
H
H
H
O
3
H
H
H
H
H
H
L
H
H
H
H
O
4
H
H
H
H
H
H
H
L
H
H
H
O
5
H
H
H
H
H
H
H
H
L
H
H
O
6
H
H
H
H
H
H
H
H
H
L
H
O
7
H
H
H
H
H
H
H
H
H
H
L
2570 tbl 02
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
Rating
Commercial
(2)
Terminal Voltage
V
TERM
–0.5 to +7.0
with Respect to
GND
V
TERM(3)
Terminal Voltage
–0.5 to
with Respect to
V
CC
+0.5
GND
T
A
Operating
0 to +70
Temperature
T
BIAS
Temperature
–55 to +125
Under Bias
T
STG
Storage
–55 to +125
Temperature
P
T
Power Dissipation
0.5
I
OUT
DC Output
Current
–60 to +120
Military
–0.5 to +7.0
Unit
V
CAPACITANCE
(T
A
= +25°C, f = 1.0MHz)
Symbol
Parameter
(1)
C
IN
Input
Capacitance
C
OUT
Output
Capacitance
Conditions
V
IN
= 0V
V
OUT
= 0V
Typ.
6
8
Max. Unit
10
pF
12
pF
2570 lnk 04
–0.5 to
V
CC
+0.5
–55 to +125
–65 to +135
–65 to +150
0.5
–60 to +120
V
°
C
°
C
°
C
W
mA
NOTE:
1. This parameter is measured at characterization but not tested.
2570 lnk 03
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.
6.3
2
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
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%
Symbol
V
IH
V
IL
I
I H
I
I L
I
I
V
IK
I
OS
V
OH
Parameter
Input HIGH Level
Input LOW Level
Input HIGH Current
(4)
Input LOW Current
(4)
Input HIGH Current
(4)
Clamp Diode Voltage
Short Circuit Current
Output HIGH Voltage
Test Conditions
(1)
Guaranteed Logic HIGH Level
Guaranteed Logic LOW Level
V
CC
= Max.
V
CC
= Max.
V
CC
= Min., I
N
= –18mA
V
CC
= Max.
(3)
, V
O
= GND
V
CC
= Min.
V
IN
= V
IH
or V
IL
I
OH
= –6mA MIL.
I
OH
= –8mA COM'L.
I
OH
= –12mA MIL.
I
OH
= –15mA COM'L.
I
OL
= 32mA MIL.
I
OL
= 48mA COM'L.
—
Min.
2.0
—
—
—
—
—
–60
2.4
2.0
—
—
—
Typ.
(2)
—
—
—
—
—
–0.7
–120
3.3
3.0
0.3
200
0.01
Max.
—
0.8
±1
±1
±1
–1.2
–225
—
—
0.5
—
1
Unit
V
V
µA
µA
µA
V
mA
V
V
V
mV
mA
2570 tbl 05
V
I
= 2.7V
V
I
= 0.5V
V
CC
= Max., V
I
= V
CC
(Max.)
V
OL
V
H
I
CC
Output LOW Voltage
Input Hysteresis
Quiescent Power Supply Current
V
CC
= Min.
V
IN
= V
IH
or V
IL
V
CC
= Max.
V
IN
= GND or V
CC
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
±5µA
at T
A
= –55°C.
6.3
3
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
POWER SUPPLY CHARACTERISTICS
Symbol
∆I
CC
I
CCD
Parameter
Quiescent Power Supply Current
TTL Inputs HIGH
Dynamic Power Supply Current
(4)
Test Conditions
(1)
V
CC
= Max.
V
IN
= 3.4V
(3)
V
CC
= Max.
Outputs Open
One Bit Toggling
50% Duty Cycle
V
CC
= Max.
Outputs Open
Toggle
E
1
,
E
2
or E
3
50% Duty Cycle
fo = 10MHz
One Input and
One Output Toggling
Min.
—
—
Typ.
(2)
0.5
0.15
Max.
2.0
0.3
Unit
mA
mA/
MHz
V
IN
= V
CC
V
IN
= GND
I
C
Total Power Supply Current
(6)
V
IN
= V
CC
V
IN
= GND
V
IN
= 3.4V
V
IN
= GND
—
1.5
4.0
mA
—
1.8
5.0
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
FCT138T
Com'l.
Symbol
Parameter
Condition
(1)
Mil.
FCT138AT
Com'l.
Mil.
FCT138CT
Com'l.
Mil.
Unit
Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max. Min.
(2)
Max.
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
Propagation Delay
A
n
to
O
n
Propagation Delay
E
1
or
E
2
to
O
n
Propagation Delay
E
3
to
O
n
C
L
= 50pF
R
L
= 500
Ω
1.5
1.5
1.5
9.0
9.0
9.0
1.5 12.0
1.5 12.5
1.5 12.5
1.5
1.5
1.5
5.8
5.9
5.9
1.5
1.5
1.5
7.8
8.0
8.0
1.5
1.5
1.5
5.1
5.2
5.2
1.5
1.5
1.5
6.0
6.1
6.1
ns
ns
ns
2570 tbl 07
NOTES:
1. See test circuit and waveforms.
2. Minimum limits are guaranteed but not tested on Propagation Delays.
6.3
4
IDT54/74FCT138T/AT/CT
FAST CMOS 1-OF-8 DECODER-WITH ENABLE
MILITARY AND COMMERCIAL TEMPERATURE RANGES
TEST CIRCUITS AND WAVEFORMS
TEST CIRCUITS FOR ALL OUTPUTS
V
CC
500
Ω
V
IN
Pulse
Generator
R
T
D.U.T.
50pF
C
L
2570 drw 04
SWITCH POSITION
Test
7.0V
Switch
Open Drain
Disable Low
Enable Low
All Other Tests
Closed
Open
V
OUT
500
Ω
2570 tbl 08
DEFINITIONS:
C
L
= Load capacitance: includes jig and probe capacitance.
R
T
=
Termination resistance: should be equal to Z
OUT
of the Pulse
Generator.
SET-UP, HOLD AND RELEASE TIMES
PULSE WIDTH
DATA
INPUT
TIMING
INPUT
ASYNCHRONOUS CONTROL
PRESET
CLEAR
ETC.
SYNCHRONOUS CONTROL
PRESET
CLEAR
CLOCK ENABLE
ETC.
t
SU
t
H
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
2570 drw 05
LOW-HIGH-LOW
PULSE
t
W
HIGH-LOW-HIGH
PULSE
1.5V
t
REM
1.5V
2570 drw 06
t
SU
t
H
PROPAGATION DELAY
ENABLE AND DISABLE TIMES
ENABLE
DISABLE
3V
CONTROL
INPUT
t
PZL
OUTPUT
NORMALLY
LOW
OUTPUT
NORMALLY
HIGH
SWITCH
CLOSED
t
PZH
SWITCH
OPEN
1.5V
0V
3.5V
1.5V
t
PHZ
0.3V
V
OH
0V
2570 drw 08
SAME PHASE
INPUT TRANSITION
t
PLH
OUTPUT
t
PLH
OPPOSITE PHASE
INPUT TRANSITION
t
PHL
t
PHL
3V
1.5V
0V
V
OH
1.5V
V
OL
3V
1.5V
0V
2570 drw 07
t
PLZ
1.5V
0V
3.5V
0.3V
V
OL
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
6.3
5
