Download PDF74HC640 PHILIPS
Document overview
- PDF pages: 6
Technical content
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FEATURES
- Octal bidirectional bus interface
- Inverting 3-state outputs
- Output capability: bus driver
- ICC category: MSI
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns
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.
| SYMBOL | PARAMETER | CONDITIONS | TYPICAL | UNIT | |
|---|---|---|---|---|---|
| HC | HCT | ||||
| t / t PHL PLH | propagation delay A to B ; n n B to A n n | C = 15 pF; V = 5 V L CC | 9 | 9 | ns |
| C I | input capacitance | 3.5 | 3.5 | pF | |
| C I/O | input/output capacitance | 10 | 10 | pF | |
| C PD | power dissipation capacitance per transceiver | notes 1 and 2 | 35 | 35 | pF |
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
ORDERING INFORMATION
See “74HC/HCT/HCU/HCMOS Logic Package Information”.
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| PIN NO. | SYMBOL | NAME AND FUNCTION |
|---|---|---|
| 1 2, 3, 4, 5, 6, 7, 8, 9 10 18, 17, 16, 15, 14, 13, 12, 11 19 20 | DIR A to A 0 7 GND B to B 0 7 OE V CC | direction control data inputs/outputs ground (0 V) data inputs/outputs output enable input (active LOW) positive supply voltage |
| inputs | inputs/outputs | ||
| OE | DIR | A n | B n |
| L L H | L H X | A=B inputs Z | inputs B=A Z |
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| SYMBOL | PARAMETER | T (°C) amb | UNIT | TEST CONDITIONS | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 74HCT | V CC (V) | WAVEFORMS | |||||||||
| +25 | −40 to +85 | −40 to +125 | |||||||||
| min. | typ. | max. | min. | max. | min. | max. | |||||
| t / t PHL PLH | propagation delay A to B n; n B to A n n | 11 | 22 | 28 | 33 | ns | 4.5 | Fig.5 | |||
| t / t PZH PZL | 3-state output enable time OE, DIR to A ; n OE, DIR to B n | 18 | 30 | 38 | 45 | ns | 4.5 | Fig.6 | |||
| t / t PHZ PLZ | 3-state output disable time OE, DIR to A ; n OE, DIR to B n | 19 | 30 | 38 | 45 | ns | 4.5 | Fig.6 | |||
| t / t THL TLH | output transition time | 5 | 12 | 15 | 18 | ns | 4.5 | Fig.5 | |||
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