The HC243 and HCT243 silicon-gate CMOS three-state bidirectional noninverting buffers are intended for two-way asynchronous communication between data buses. They have high-drive-current outputs that enable high-speed operation when driving large bus capacitances. These circuits possess the low power dissipation of CMOS circuits and have speeds comparable to low-power Schottky TTL circuits. They can drive 15 LSTTL loads.
The states of the output-enable (OEB\, OEA) inputs determine both the direction of flow (A to B, B to A), and the three-state mode.
Typical Propagation Delay (A to B, B to A) of 7ns at VCC = 5V, CL = 15pF, TA = 25°C
Three-State Outputs
Buffered Inputs
Fanout (Over Temperature Range)
Standard Outputs . . . 10 LSTTL Loads
Bus Driver Outputs . . . . 15 LSTTL Loads
Wide Operating Temperature Range . . . 55°C to 125°C
Balanced Propagation Delay and Transition Times
Significant Power Reduction Compared to LSTTL Logic ICs
HC Types
2V to 6V Operation
High Noise Immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V
HCT Types
4.5V to 5.5V Operation
Direct LSTTL Input Logic Compatibility, VIL = 0.8V (Max), VIH = 2V (Min)
