SN74AHCT573NSRE4

Overview

The SN74AHCT573NSRE4 is an octal transparent D-type latch with 3-state outputs manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature range from -40°C to +85°C. The device features TTL-voltage compatible inputs, high-impedance output states controlled by a buffered OE input, and ESD protection exceeding JESD 22 standards. Propagation delays are specified at 6.5 ns (max) for D-to-Q transitions and 10 ns (max) for OE-to-Q transitions under standard load conditions.

Feature Summary

• TTL-voltage compatible inputs ensure direct interfacing with standard logic families without level shifting requirements.
• Buffered output-enable control allows the eight outputs to enter a high-impedance state, preventing bus loading during inactive periods.
• Transparent latch operation enables Q outputs to follow D inputs when the latch-enable signal is active, facilitating real-time data capture.

Applications

• Bus-oriented memory mapping and address decoding circuits
• Parallel-to-serial conversion interfaces requiring temporary data storage
• High-speed digital systems utilizing 3-state bus architectures

Procurement Notes

Verify the specific ordering suffix 'R' indicates tape and reel packaging configuration. Confirm that the 'E4' suffix denotes lead-free material composition and RoHS compliance status. Ensure the NS package designation matches the required SOIC-20 footprint for PCB layout compatibility. Cross-reference the manufacturer's latest datasheet revision to confirm current production status and parameter validity.

Selection Notes

Select this component when TTL-compatible logic levels are required alongside CMOS performance characteristics. The AHCT series provides faster switching speeds compared to standard HC devices while maintaining electrical compatibility with TTL inputs. Consider the 3-state output capability if the design requires shared bus lines or multiplexed data paths where high-impedance isolation is necessary.

Part Context

This part belongs to the SN74AHCT573 family of octal transparent D-type latches. The family includes variants with different package types such as DIP, SOIC, TSSOP, and SSOP. All members share identical internal logic functionality but differ in physical dimensions, thermal characteristics, and manufacturing packaging formats suitable for various surface-mount and through-hole assembly processes.

Replacement Considerations

SN74AHCT573DWRE4: Same logic function and specifications in SOIC-20 tube packaging instead of tape and reel.

FAQ

How does the output-enable input affect internal latch operations?

The OE input controls only the external output drivers. It places outputs in a high-impedance state without affecting the internal latching mechanism, allowing new data to be entered or old data retained while outputs are disabled.

What is the purpose of tying OE to VCC through a pullup resistor?

Tying OE to VCC via a pullup resistor ensures the outputs default to a high-impedance state during power-up or power-down events, preventing unintended bus driving before the device reaches stable operating conditions.