DESCRIPTION · Octal bidirectional bus interface The 74HC/HCT640 are high-speed Si-gate CMOS devices · Inverting 3-state outputs and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC · Output capability: bus driver standard no. 7A. · ICC category: MSI 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 TYPICAL SYMBOL PARAMETER CONDITIONS UNIT HC HCT tPHL/ tPLH propagation delay CL = 15 pF; VCC = 5 V 9 9 ns An to Bn; Bn to An CI input capacitance 3.5 3.5 pF CI/O input/output capacitance 10 10 pF CPD power dissipation capacitance