54ACTQ657 Quiet Series Octal Bidirectional Transceiver with 8-Bit Parity Generator/Checker and TRI-STATE Outputs
54ACTQ657 Quiet Series Octal Bidirectional Transceiver with 8-Bit Parity Generator/Checker and TRI-STATE � Outputs
The ACTQ657 contains eight non-inverting buffers with TRI-STATE outputs and an 8-bit parity generator/checker. Intended for bus oriented applications, the device combines the '245 and the '280 functions in one package. The ACTQ utilizes NSC Quiet Series technology to guarantee quiet output switching and improved dynamic threshold performance. FACT Quiet SeriesTM features GTOTM output control and undershoot corrector in addition to a split ground bus for superior performance.Features
n Guaranteed simultaneous switching noise level and dynamic threshold performance n Combines the '245 and the '280 functions in one package n Outputs source/sink mA n 'ACTQ has TTL-compatible inputs n Standard Microcircuit Drawing (SMD) 5962-92197
GTOTM is a trademark of National Semiconductor Corporation. TRI-STATE is a registered trademark of National Semiconductor Corporation. FACT Quiet SeriesTM is a trademark of Fairchild Semiconductor Corporation.
Description Data Inputs/TRI-STATE Outputs Data Inputs/TRI-STATE Outputs Transmit/Receive Input Enable Input Parity Input/TRI-STATE Output ODD/EVEN Parity Input Error TRI-STATE Output
The Transmit/Receive (T/R) input determines the direction of the data flow through the bidirectional transceivers. Transmit (active HIGH) enables data from the A port to the B port; Receive (active LOW) enables data from the B port to the A port. The Output Enable (OE) input disables the parity and ERROR outputs and both the A and B ports by placing them in a HIGH-Z condition when the Output Enable input is HIGH. When transmitting (T/R HIGH), the parity generator detects whether an even or odd number of bits on the A port are HIGH and compares these with the condition of the parity select (ODD/EVEN). If the Parity Select is HIGH and an even number of A inputs are HIGH, the Parity output is HIGH. In receiving mode (T/R LOW), the parity select and number of HIGH inputs on port B are compared to the condition of the Parity input. If an even number of bits on the B port are HIGH, the parity select is HIGH, and the PARITY input is HIGH, then ERROR will be HIGH to indicate no error. If an odd number of bits on the B port are HIGH, the parity select is HIGH, and the PARITY input is HIGH, the ERROR will be LOW indicating an error.