74AHC138 Philips Semiconductors, 74AHC138 Datasheet - Page 2

• Manufacturer Part Number: 74AHC138
• Description: 3-to-8 line decoder/demultiplexer; inverting
• Manufacturer: Philips Semiconductors

Philips Semiconductors
FEATURES
QUICK REFERENCE DATA
GND = 0 V; T
Notes
1. C
2. The condition is V
1999 Sep 27
t
C
C
C
PHL
SYMBOL
ESD protection:
HBM EIA/JESD22-A114-A
exceeds 2000 V
MM EIA/JESD22-A115-A
exceeds 200 V
CDM EIA/JESD22-C101
exceeds 1000 V
Balanced propagation delays
All inputs have Schmitt-trigger
actions
Multiple input enable for easy
expansion
Ideal for memory chip select
decoding
Inputs accept voltages higher than
V
For AHC only:
operates with CMOS input levels
For AHCT only:
operates with TTL input levels
Specified from
I
O
PD
3-to-8 line decoder/demultiplexer; inverting
40 to +85 and +125 C.
CC
P
f
f
C
V
i
o
/t
D
CC
PD
= input frequency in MHz;
L
PLH
= output frequency in MHz;
(C
= output load capacitance in pF;
= C
is used to determine the dynamic power dissipation (P
= supply voltage in Volts.
L
PD
V
amb
CC
propagation delay A
propagation delay E
input capacitance
output capacitance
power dissipation capacitance
V
2
CC
= 25 C; t
f
2
o
) = sum of outputs;
I
f
= GND to V
i
+
PARAMETER
r
= t
(C
f
L
3.0 ns.
n
3
CC
V
to Y
to Y
CC
.
2
n
n
The ‘138’ features three enable inputs: two active LOW (E
DESCRIPTION
The 74AHC/AHCT138 are high-speed Si-gate CMOS devices and are pin
compatible with low power Schottky TTL (LSTTL). They are specified in
compliance with JEDEC standard No. 7A.
The 74AHC/AHCT138 decoders accept three binary weighted address inputs
(A
outputs (Y
active HIGH (E
is HIGH.
This multiple enable function allows easy parallel expansion of the ‘138’ to a
1-of-32 (5 to 32 lines) decoder with just four ‘138’ ICs and one inverter.
The ‘138’ can be used as an eight output demultiplexer by using one of the
active LOW enable inputs as the data input and the remaining enable inputs as
strobes. Unused enable inputs must be permanently tied to their appropriate
active HIGH or LOW state.
The ‘138’ is identical to the ‘238’ but has inverting outputs.
; E
f
o
0
n
) where:
, A
to Y
1
and A
n
0
to Y
C
C
V
C
notes 1 and 2
2
I
L
L
L
) and when enabled, provide 8 mutually exclusive active LOW
3
= V
= 15 pF; V
= 15 pF; V
= 50 pF; f = 1 MHz;
). Every output will be HIGH unless E
7
).
2
CONDITIONS
CC
or GND
D
in W).
CC
CC
= 5 V
= 5 V
4.4
4.2
3.0
4.0
18
AHC
TYPICAL
1
4.4
4.3
3.0
4.0
23
and E
Product specification
AHCT
74AHCT138
74AHC138;
1
and E
2
are LOW and E
2
pF
pF
ns
ns
pF
) and one
UNIT
3