Philips Semiconductors
Product specification
Octal buffer/line driver; 3-state
74HC/HCT244
The 74HC/HCT244 are octal non-inverting buffer/line
drivers with 3-state outputs. The 3-state outputs are
controlled by the output enable inputs 1OE and 2OE.
A HIGH on nOE causes the outputs to assume a high
impedance OFF-state. The “244” is identical to the “240”
but has non-inverting outputs.
FEATURES
• Output capability: bus driver
• ICC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT244 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.
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns
TYPICAL
SYMBOL
PARAMETER
propagation delay
CONDITIONS
UNIT
ns
HC
HCT
11
tPHL/ tPLH
CL = 15 pF; VCC = 5 V
9
1An to 1Yn;
2An to 2Yn
CI
input capacitance
3.5
35
3.5
35
pF
pF
CPD
power dissipation capacitance per buffer
notes 1 and 2
Notes
1. CPD is used to determine the dynamic power dissipation (PD in µW):
2
PD = CPD × VCC2 × fi + ∑ (CL × VCC × fo) where:
fi = input frequency in MHz
fo = output frequency in MHz
2
∑ (CL × VCC × fo) = sum of outputs
CL = output load capacitance in pF
V
CC = supply voltage in V
2. For HC the condition is VI = GND to VCC
For HCT the condition is VI = GND to VCC − 1.5 V
ORDERING INFORMATION
See “74HC/HCT/HCU/HCMOS Logic Package Information”.
December 1990
2