74ACQ573PC

Latches Overview

The 74ACQ573PC is an octal D-type transparent latch with three-state outputs manufactured by Fairchild Semiconductor. It operates on a single supply voltage ranging from 2.0V to 6.0V and functions within a temperature range of -40°C to +85°C. The device features buffered common Latch Enable (LE) and Output Enable (OE) inputs, allowing data transparency when LE is high and storage upon transition to low. Outputs source and sink up to 24 mA. It utilizes Quiet Series technology for improved dynamic threshold performance and reduced simultaneous switching noise.

Latches Feature Summary

• Utilizes FACT Quiet Series technology including GTO output control and undershoot correction for superior noise performance.
• Features inputs and outputs positioned on opposite sides of the package to facilitate easy interface with microprocessors.
• Provides guaranteed pin-to-pin skew AC performance and improved latch-up immunity.

Latches Applications

• High-speed data latching in digital systems
• Microprocessor memory address/data bus buffering
• Portable battery-powered equipment requiring low power consumption

Latches Procurement Notes

Verify that the component corresponds to the original Fairchild Semiconductor manufacturing origin rather than subsequent acquisitions, as the datasheet identifies Fairchild as the producer. Confirm the PDIP-20 package designation matches the specific ordering code suffix 'PC' to ensure physical compatibility with existing footprints. Check for any RoHS compliance documentation updates relative to the January 1990/Revised October 2000 publication date.

Latches Selection Notes

Select this component when bidirectional data flow buffering is required due to its transparent latch operation mode. It is suitable for applications needing high drive capability with 24 mA output current. Consider the 2.0V to 6.0V operating range for versatility across different logic families. Ensure the design accounts for the specific propagation delays and setup times defined in the AC electrical characteristics tables.

Latches Part Context

This part belongs to the 74ACQ/ACTQ family of octal latches. It is functionally identical to the 74ACQ373 but differs in pinout configuration, placing inputs and outputs on opposite sides. This layout optimization simplifies PCB routing for microprocessor interfaces compared to standard symmetric layouts found in other logic families.

Latches Replacement Considerations

The 74ACQ373 serves as a functional equivalent with identical logic operations but a different pin arrangement. Other variants in the series include SOIC (SC), SOP (SJ), TSSOP (MTC), and QSOP (QSC) packages for the ACQ version, and similar packages for the ACTQ version which is restricted to 4.5V to 5.5V operation.

Latches FAQ

How does the 74ACQ573 handle data during the latch enable transition?

When the Latch Enable (LE) input is HIGH, the device is transparent, meaning outputs follow inputs. When LE transitions from HIGH to LOW, the data present at the inputs at that instant is stored in the latches.

What is the purpose of the separate Output Enable (OE) input?

The OE input controls the three-state buffers. When OE is LOW, outputs are enabled. When OE is HIGH, outputs enter a high-impedance state, isolating them from the circuit without affecting the data stored in the latches.