DESCRIPTION
The M74HCT643 is an advanced high-speed CMOS OCTAL BUS TRANSCEIVER (3-STATE) fabricated with silicon gate C2MOS technology.
This IC is intended for two-way asynchronous communication between data buses, and the direction of data transmission is determined by DIR input. The enable input G can be used to disable the device so that the buses are effectively isolated.
All inputs are equipped with protection circuits against static discharge and transient excess voltage.
All floating bus terminals during High Z State must be held HIGH or LOW.

■ HIGH SPEED:
   tPD = 13ns (TYP.) at VCC = 4.5V
■ LOW POWER DISSIPATION:
   ICC = 4µA(MAX.) at TA=25°C
■ COMPATIBLE WITH TTL OUTPUTS :
   VIH = 2V (MIN.) VIL = 0.8V (MAX)
■ SYMMETRICAL OUTPUT IMPEDANCE:
   |IOH| = IOL = 6mA (MIN)
■ BALANCED PROPAGATION DELAYS:
   tPLH ≅ tPHL
■ PIN AND FUNCTION COMPATIBLE WITH
   74 SERIES 643