I74F657D,112

Overview

The I74F657D,112 is an octal transceiver with an integrated 8-bit parity generator and checker. It combines the functionality of a 3-state buffer and parity logic in a single package. The device features high-impedance base inputs to reduce bus loading and provides strong output drive capabilities for reliable data transmission across bidirectional buses.

Feature Summary

• Integrates octal transceiver buffers with 8-bit parity generation and checking functions
• Features high-impedance base inputs to minimize loading on connected circuits
• Provides 3-state outputs with enhanced current sinking and sourcing capabilities
• Supports configurable odd or even parity selection via dedicated control input

Applications

• Bus-oriented applications requiring bidirectional data transfer
• Systems needing combined data routing and error detection logic
• Industrial environments requiring extended temperature operation ranges

Procurement Notes

Verify that the specific ordering code matches the required industrial temperature range and plastic small outline package configuration. Confirm compatibility with existing system voltage levels and signal integrity requirements before finalizing procurement decisions.

Selection Notes

Select this component when design constraints require consolidating both data buffering and parity checking into a single footprint. Evaluate the trade-off between the reduced bus loading provided by the high-impedance inputs and the specific drive strength requirements of the target application.

Part Context

This part belongs to the 74F series of high-speed logic devices originally developed by Philips Semiconductors. It serves as a specialized solution for systems where data integrity monitoring is critical alongside standard bus interfacing tasks.

Replacement Considerations

Direct replacements include the N74F657D for commercial temperature variants. Ensure pinout compatibility and verify that alternative packages meet the physical space constraints of the original design.

FAQ

How does the device handle parity errors?

When receiving data, the device polls the B port bits. If the bit count and parity input do not match the selected ODD/EVEN setting, the ERROR output is asserted to indicate a mismatch.

What determines the direction of data flow?

The Transmit/Receive (T/R) input controls the direction. An active HIGH state enables transmission from A ports to B ports, while an active LOW state enables reception from B ports to A ports.