December 1990 2
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state;
inverting 74HC/HCT240
FEATURES
•Output capability: bus driver
•ICC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT240 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 74HC/HCT240 are octal 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 “240” is identical to the “244” but has
inverting outputs.
QUICK REFERENCE DATA
GND = 0 V; Tamb =25°C; tr=t
f= 6 ns
Notes
1. CPD is used to determine the dynamic power dissipation (PD in µW):
PD=C
PD × VCC2× fi+ ∑ (CL× VCC2 × fo) where:
fi= input frequency in MHz
fo= output frequency in MHz
∑ (CL× VCC2× fo) = sum of outputs
CL= output load capacitance in pF
VCC = 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”
.
SYMBOL PARAMETER CONDITIONS TYPICAL UNIT
HC HCT
tPHL/ tPLH propagation delay
1An to 1Yn;
2An to 2Yn
CL= 15 pF; VCC =5 V99ns
C
Iinput capacitance 3.5 3.5 pF
CPD power dissipation capacitance per buffer notes 1 and 2 30 30 pF