Texas Instruments CY74FCT138CTSOC, CY74FCT138CTQCT, CY74FCT138CTQC, CY74FCT138ATSOCT, CY74FCT138ATSOC Datasheet
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1-of-8 Decoder
CY54/74FCT138T
SCCS013 - May 1994 - Revised February 2000
Data sheet acquired from Cypress Semiconductor Corporation.
Data sheet modified to remove devices not offered.
Copyright © 2000, Texas Instruments Incorporated
Features
• Function, pinout, and drive compatible with FCT and
F logic
• FCT-C speed at 5.0 ns max. (Com’l),
FCT-A speed at 5.8 ns max. (Com’l)
• Reduced V
OH
(typically = 3.3V) versions of equivalent
FCT functions
• Edge-rate control circuitry for significantly improved
noise characteristics
• Power-off disable feature
• ESD > 2000V
• Matched rise and fall times
• Fully compatible with TTL input and output logic levels
• Extended commercial range of −40˚C to +85˚C
• Sink current 64 mA (Com’l),
32 mA (Mil)
Source current 32 mA (Com’l),
12 mA (Mil)
• Dual 1-of-8 decoder with enables
Functional Description
The FCT138T is a 1-of-8 decoder. The FCT138T accepts
three binary weighted inputs (A
0,A1,A2
) and, when enabled,
provides eight mutually exclusive active LOW outputs
(
O0–O7). The FCT138T features three enable inputs, two
active LOW (
E1, E2) and one active HIGH (E3).
All inputs will be HIGH unless
E1and E2are LOW and E3is
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 FCT138T devices and one inverter.
The outputs are designed with a power-off disable feature to
allow for liv e insertion of boards.
Pin Description
Name Description
A Address Inputs
E1−E
2
Enable Inputs (Active LOW)
E
3
Enable Input (Active HIGH)
O Outputs
Logic Block Diagram Pin Configurations
1
2
3
4
5
6
7
8
A
1
A
2
E
1
E
2
E
3
O
7
V
CC
GND
FCT138T–2
Top View
4
8
9
10
11
12
765
15 16 17 18
3
2
1
20
13
14
19
E3E2E
1
O
2
O
4
O
5
O
1
O
6
NC
A
1
NC
NC
V
CC
O
0
O
7
GND A
0
O
3
Top View
DIP/SOIC/QSOP
A
2
LCC
NC
16
15
14
13
12
11
10
9
O
4
O
5
O
6
O
7
O
0
O
1
O
2
O
3
E
1
A2A
1
A
0
E2E
3
FCT138T–1
A
0
O
4
O
5
O
6
O
0
O
1
O
2
O
3
FCT138T–3
CY54/74FCT138T
2
]
Maximum Ratings
[2, 3]
(Above which the useful life may be impaired. For user
guidelines, not tested.)
Storage Temperature .................................–65°C to +150°C
Ambient Temperature with
Power Applied.............................................–65°C to +135°C
Supply Voltage to Ground Potential...............–0.5V to +7.0V
DC Input Voltage............................................–0.5V to +7.0V
DC Output Voltage.........................................–0.5V to +7.0V
DC Output Current (Maximum Sink Current/Pin).......120 mA
Power Dissipation..........................................................0.5W
Static Discharge Voltage............................................>2001V
(per MIL-STD-883, Method 3015)
Function Table
[1]
Inputs Outputs
E
1
E
2
E
3
A
0
A
1
A
2
O
0
O
1
O
2
O
3
O
4
O
5
O
6
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
Operating Range
Range Range
Ambient
Temperature V
CC
Commercial All –40°C to +85°C 5V ± 5%
Military
[4]
All –55°C to +125°C 5V ± 10%
Electrical Characteristics Over the Operating Range
Parameter Description Test Conditions Min. Typ.
[5]
Max. Unit
V
OH
Output HIGH Voltage VCC=Min., IOH=–32 mA Com’l 2.0 V
V
OH
Output HIGH Voltage VCC=Min., IOH=–15 mA Com’l 2.4 3.3 V
V
OH
Output HIGH Voltage VCC=Min., IOH=–12 mA Mil 2.4 3.3 V
V
OL
Output LOW Voltage VCC=Min., IOL=64 mA Com’l 0.3 0.55 V
VCC=Min., IOL=32 mA Mil 0.3 0.55 V
V
IH
Input HIGH Voltage 2.0 V
V
IL
Input LOW Voltage 0.8 V
V
H
Hysteresis
[6]
All inputs 0.2 V
V
IK
Input Clamp Diode Voltage VCC=Min., IIN=–18 mA –0.7 –1.2 V
I
I
Input HIGH Current VCC=Max., VIN=V
CC
5 µA
I
IH
Input HIGH Current VCC=Max., VIN=2.7V ±1 µA
I
IL
Input LOW Current VCC=Max., VIN=0.5V ±1 µA
I
OS
Output Short Circuit Current
[7]
VCC=Max., V
OUT
=0.0V –60 –120 –225 mA
I
OFF
Power-Off Disable VCC=0V, V
OUT
=4.5V ±1 µA
Notes:
1. H = HIGH Voltage Level. L = LOW Voltage Level. X = Don’t Care.
2. Unless otherwise noted, these limits are over the operating free-air temperature range.
3. Unused inputs must always be connected to an appropriate logic voltage level, preferably either V
CC
or ground.
4. T
A
is the “instant on” case temperature.
5. Typical values are at V
CC
=5.0V, TA=+25˚C ambient.
6. This parameter is specified but not tested.
7. Not more than one output should be shorted at a time. Duration of short should not exceed one second. The use of high-speed test apparatus and/or sample
and hold techniques are preferable in order to minimize internal chip heating and more accurately reflect operational values. Otherwise prolonged shorting of
a high output may raise the chip temperature well above normal and thereby cause invalid readings in other parametric tests. In any sequence of parameter
tests, I
OS
tests should be performed last.
CY54/74FCT138T
3
Capacitance
[6]
Parameter Description Typ.
[5]
Max. Unit
C
IN
Input Capacitance 5 10 pF
C
OUT
Output Capacitance 9 12 pF
Power Supply Characteristics
Parameter Description Test Conditions Typ.
[5]
Max. Unit
I
CC
Quiescent Power Supply Current VCC=Max., VIN<0.2V,
V
IN
> VCC–0.2V
0.1 0.2 mA
∆I
CC
Quiescent Power Supply Current
(TTL inputs)
VCC=Max., VIN=3.4V,
[8]
f1=0, Outputs Open
0.5 2.0 mA
I
CCD
Dynamic Power Supply
Current
[9]
VCC=Max., One Input Toggling,
50% Duty Cycle, Outputs Open,
V
IN
< 0.2V or VIN> VCC–0.2V
0.06 0.12 mA/MHz
I
C
Total Power Supply Current
[10]
VCC=Max., f1=10 MHz,
50% Duty Cycle, Outputs Open, Toggle
E1, E2, or E3, One Output Toggling
,
VIN< 0.2V or VIN> VCC–0.2V
0.7 1.4 mA
VCC=Max., f1=10 MHz,
50% Duty Cycle, Outputs Open, Toggle
E1, E2, or E3, One Output Toggling,
V
IN
=3.4V or VIN=GND
1.0 2.4 mA
Notes:
8. Per TTL driven input (V
IN
=3.4V); all other inputs at VCC or GND.
9. This parameter is not directly testable, but is derived for use in Total Power Supply calculations.
10. I
C
=I
QUIESCENT
+ I
INPUTS
+ I
DYNAMIC
IC=ICC+∆ICCDHNT+I
CCD(f0
/2 + f1N1)
I
CC
= Quiescent Current with CMOS input levels
∆I
CC
= Power Supply Current for a TTL HIGH input (VIN=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
0
= Clock frequency for registered devices, otherwise zero
f
1
= Input signal frequency
N
1
= Number of inputs changing at f
1
All currents are in milliamps and all frequencies are in megahertz.
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