CY54FCT138T, CY74FCT138T
1-OF-8 DECODERS
SCCS013B 鈥?MAY 1994 鈥?REVISED OCTOBER 2001
D
D
D
D
D
D
D
D
D
D
description
NC 鈥?No internal connection
The 鈥橣CT138T devices are 1-of-8 decoders. These devices accept three binary weighted inputs (A
0
, A
1
, A
2
)
and, when enabled, provide eight mutually exclusive active-low outputs (O
0
鈥揙
7
). The 鈥橣CT138T devices
feature three enable inputs: two active low (E
1
, E
2
) and one active high (E
3
).
All outputs are 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 (five lines to 32 lines) decoder with just four 鈥橣CT138T devices and one
inverter.
These devices are fully specified for partial-power-down applications using I
off
. The I
off
circuitry disables the
outputs, preventing damaging current backflow through the device when it is powered down.
PIN DESCRIPTION
NAME
A
E1, E2
E3
O
DESCRIPTION
Address inputs
Enable inputs (active low)
Enable input (active high)
Outputs
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright
錚?/div>
2001, Texas Instruments Incorporated
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303
鈥?/div>
DALLAS, TEXAS 75265
GND
NC
O
6
O
5
Function, Pinout, and Drive Compatible
With FCT and F Logic
Reduced V
OH
(Typically = 3.3 V) Versions of
Equivalent FCT Functions
Edge-Rate Control Circuitry for
Significantly Improved Noise
Characteristics
I
off
Supports Partial-Power-Down Mode
Operation
Matched Rise and Fall Times
Fully Compatible With TTL Input and
Output Logic Levels
Dual 1-of-8 Decoder With Enables
ESD Protection Exceeds JESD 22
鈥?2000-V Human-Body Model (A114-A)
鈥?200-V Machine Model (A115-A)
鈥?1000-V Charged-Device Model (C101)
CY54FCT138T
鈥?32-mA Output Sink Current
鈥?12-mA Output Source Current
CY74FCT138T
鈥?64-mA Output Sink Current
鈥?32-mA Output Source Current
CY54FCT138T . . . D PACKAGE
CY74FCT138T . . . Q OR SO PACKAGE
(TOP VIEW)
A
0
A
1
A
2
E
1
E
2
E
3
O
7
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
O
0
O
1
O
2
O
3
O
4
O
5
O
6
CY54FCT138T . . . L PACKAGE
(TOP VIEW)
A
1
A
0
NC
V
CC
O
0
A
2
E
1
NC
E
2
E
3
3
4
5
6
7
8
2 1 20 19
18
17
16
15
14
9 10 11 12 13
O
1
O
2
NC
O
3
O
4
O
7
1
1
2
3
4
5
6
7
