Datasheet

September 1993 2
Philips Semiconductors Product specification
Dual 2-to-4 line decoder/demultiplexer 74HC/HCT139
FEATURES
• Demultiplexing capability
• Two independent 2-to-4 decoders
• Multifunction capability
• Active LOW mutually exclusive outputs
• Output capability: standard
• I
CC
category: MSI
GENERAL DESCRIPTION
The 74HC/HCT139 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). It is specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT139 are high-speed, dual 2-to-4 line
decoder/multiplexers. This device has two independent
decoders, each accepting two binary weighted inputs
(nA
0
and nA
1
) and providing four mutually exclusive active
LOW outputs (nY
0
to nY3). Each decoder has an active
LOW enable input (nE).
When nE is HIGH, every output is forced HIGH. The
enable can be used as the data input for a 1-to-4
demultiplexer application.
The “139” is identical to the HEF4556 of the HE4000B
family.
QUICK REFERENCE DATA
GND = 0 V; T
amb
= 25 °C; t
r
= t
f
= 6 ns
Notes
1. C
PD
is used to determine the dynamic power dissipation (P
D
in µW):
P
D
= C
PD
× V
CC
2
× f
i
+∑(C
L
× V
CC
2
× f
o
) where:
f
i
= input frequency in MHz
f
o
= output frequency in MHz
∑ (C
L
× V
CC
2
× f
o
) = sum of outputs
C
L
= output load capacitance in pF
V
CC
= supply voltage in V
2. For HC the condition is V
I
= GND to V
CC
For HCT the condition is V
I
= GND to V
CC
− 1.5 V
APPLICATIONS
• Memory decoding or data-routing
• Code conversion
ORDERING INFORMATION
See “74HC/HCT/HCU/HCMOS Logic Package Information” .
SYMBOL PARAMETER CONDITIONS
TYPICAL
UNIT
HC HCT
t
PHL
/ t
PLH
propagation delay C
L
= 15 pF; V
CC
= 5 V
nA
n
to nY
n
11 13 ns
n
E
3
to nY
n
10 13 ns
C
I
input capacitance 3.5 3.5 pF
C
PD
power dissipation capacitance per multiplexer notes 1 and 2 42 44 pF