74ABT899A,623

Overview

The NXP USA Inc. 74ABT899A,623 is a 9-bit dual latch transceiver with an integrated 8-bit parity generator and checker. It features symmetric A and B bus functions, selectable generate or feed-through parity modes for both directions, and independent transparent latches. The device supports ODD/EVEN parity selection and continuously checks parity via ERRA and ERRB error outputs. It provides +64 mA/-32 mA output capability, power-up 3-State, and live insertion/extraction support.

Feature Summary

• Symmetric A and B bus functions allow identical operation in either direction.
• Independent transparent latches enable simultaneous reading and latching of data on both buses.
• Selectable parity generation or feed-through modes facilitate flexible data integrity checking.
• Continuous parity error checking is provided via dedicated active-low error signal outputs.

Applications

• High-speed data bus systems requiring parity verification
• Memory interface circuits with latch capabilities
• Data communication links utilizing bidirectional transfer
• Systems supporting live insertion and extraction protocols

Procurement Notes

Verify the specific suffix '623' against current manufacturer documentation to confirm package type and temperature range availability. Confirm that the component meets required RoHS compliance standards for the intended application environment. Ensure compatibility with existing board layouts regarding the selected package dimensions and pin configuration before finalizing procurement decisions.

Selection Notes

Select this component when designing systems requiring high-performance 9-bit bidirectional data transfer with built-in error detection. Consider the ABT logic family characteristics for speed and drive strength requirements. Evaluate the need for independent latch control and simultaneous parity generation versus feed-through modes based on system architecture constraints.

Part Context

This part belongs to the 74ABT series of advanced BiCMOS logic devices. It serves as a specialized transceiver combining data transfer with robust parity checking capabilities. The device is designed for applications demanding high-speed operation and reliable data integrity monitoring within complex digital systems.

Replacement Considerations

Public confirmed substitute part numbers: SN74F86NSR, SN74F86D, SN74F86DR.

FAQ

How does the SEL input affect parity operation?

When SEL is Low, the device generates parity from the input data. When SEL is High, it operates in feed-through mode, passing the incoming parity bit without modification.

What is the function of the ODD/EVEN input?

The ODD/EVEN input selects the parity type. A Low level configures the device for EVEN parity, while a High level configures it for ODD parity.

Can the device check parity while outputs are in 3-State?

Yes, the 74ABT899 continuously checks the parity of both A and B bus latches via ERRA and ERRB outputs, even when both buses are in the 3-State condition.