74HCT640D 查看數據表（PDF） - Philips Electronics
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74HCT640D Datasheet PDF : 6 Pages
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Philips Semiconductors
Octal bus transceiver; 3-state; inverting
Product specification
74HC/HCT640
FEATURES
• Octal bidirectional bus interface
• Inverting 3-state outputs
• Output capability: bus driver
• ICC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT640 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/HCT640 are octal transceivers featuring
inverting 3-state bus compatible outputs in both send and
receive directions.
The “640” features an output enable (OE) input for easy
cascading and a send/receive (DIR) for direction control.
OE controls the outputs so that the buses are effectively
isolated. The “640” is similar to the “245” but has inverting
outputs.
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns
SYMBOL
PARAMETER
CONDITIONS
tPHL/ tPLH
CI
CI/O
CPD
propagation delay
An to Bn;
Bn to An
input capacitance
input/output capacitance
power dissipation capacitance
per transceiver
CL = 15 pF; VCC = 5 V
notes 1 and 2
Notes
1. CPD is used to determine the dynamic power dissipation (PD in µW):
PD = CPD × 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
TYPICAL
HC HCT
99
UNIT
ns
3.5 3.5 pF
10 10 pF
35 35 pF
ORDERING INFORMATION
See “74HC/HCT/HCU/HCMOS Logic Package Information”.
March 1988
2
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