SN74ALS563BN

Overview

The SN74ALS563BN is an octal D-type transparent 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 a commercial temperature range of 0°C to 70°C. The device features inverting logic, where Q outputs follow the complements of D inputs while the latch-enable (LE) signal is high. Key electrical characteristics include a low-level output current of 24 mA and a high-level output current of -2.6 mA at 5V. Propagation delays from D to Q are specified between 3 ns and 18 ns depending on transition direction.

Feature Summary

• Features 3-state outputs designed for driving highly capacitive or low-impedance loads directly without interface components.
• Transparent latch operation allows data input tracking during the high state of the latch-enable signal.
• Buffered output-enable input isolates outputs into a high-impedance state without affecting internal latch operations.

Applications

• Implementing buffer registers
• I/O port interfacing
• Bidirectional bus drivers
• Working registers

Procurement Notes

Verify the specific ordering suffix 'BN' corresponds to the PDIP package and tube packaging configuration. Confirm that the catalog version matches the required commercial operating temperature range of 0°C to 70°C. Ensure compatibility with standard TTL-compatible input levels for the ALS series logic family.

Selection Notes

Select this component when designing systems requiring octal latching with bus-driven capabilities. The ALS series offers faster switching speeds compared to standard LS logic. Consider the 24 mA low-level drive capability for direct load interfacing. Verify pinout compatibility if replacing older variants in existing board layouts.

Part Context

This part belongs to the SN74ALS563B family of octal transparent latches. It is distinct from flip-flops as it lacks edge-triggering, relying instead on level-sensitive latch enable control. The device is part of the broader 74-series logic ecosystem, specifically optimized for speed and power consumption trade-offs characteristic of the Advanced Low-power Schottky technology.

Replacement Considerations

SN74ALS563BDW (SOIC Package)

FAQ

How does the latch-enable (LE) input affect data storage?

When LE is high, the outputs track the inverted data inputs. When LE goes low, the outputs latch and hold the inverse of the data present at that moment.

What is the function of the OE input?

The buffered output-enable (OE) input controls the 3-state condition of the outputs, placing them in a high-impedance state to prevent bus loading without altering the stored data inside the latches.