SN54LS638

The SN54LS638 is a type of octal bus transceiver, which is designed for asynchronous two way communication betw een open-collector and 3-state buses. The SN54LS638 transmits data from the B bus to the A bus depending upon the le vel at the direction control input. The enable input is able to be used to disable the device so the buses are isolated.

Features of SN54LS638 are: (1)bidirectional bus transceiver in high density 20-pin packages; (2)hysteresis at bus in puts improves noise margins; (3)choice of trues or inverting logic; (4)A bus outputs are open-collector, B bus outputs are 3-state.

The absolute maximum ratings and electrical characteristics of the SN54LS638 can be summarized as: (1)supply volt age: 7V; (2)input voltage: 7V;(3)operating free air temperature range:-55 to 125;(4)storage temperature rang:-65 to 150; (5)off-state output voltage: 5.5V. Electrical characteristics: (1)high-level input voltage: 2V min; (2)low-level input voltage: 0.5V max; (3)input clamp voltage(VCC=min, I1=-18mA): -1.5V max; (4)low level input current(VC C=max, V1=0.4V):-0.4mA max; (5)short-circuit output current(VCC=max):-40mA min and-225mA max, etc.