SN74ALS843NT

Overview

The SN74ALS843NT is a 9-bit bus-interface D-type latch manufactured by Texas Instruments. It features three-state outputs and operates within a supply voltage range of 4.5 V to 5.5 V. The device provides a propagation delay time of 18 ns, with a low-level output current capability of 32 mA and a high-level output current of -2.6 mA. It is housed in a 24-pin Plastic Dual In-Line Package (PDIP) with a lead pitch of 0.300 inches. The component supports TTL input levels and includes clear and preset functionality for data control.

Feature Summary

• Provides nine-bit parallel data storage with transparent latching behavior
• Features three-state outputs for direct bus interfacing applications
• Includes dedicated clear and preset inputs for immediate data control

Applications

• Parallel data buffering in digital systems
• Bus interface circuits requiring tri-state isolation
• High-speed data storage modules

Procurement Notes

Verify the specific ordering suffix 'NT' against the manufacturer's current datasheet to confirm package type and temperature grade. Ensure compatibility with existing PCB footprints for the PDIP-24 configuration. Confirm RoHS compliance status if required for the target assembly process. Cross-reference pin assignments with the official schematic to prevent integration errors during design implementation.

Selection Notes

Select this component when nine-bit latching with tri-state bus driving is required. The ALS series offers improved speed over standard 74LS logic while maintaining compatible power consumption profiles. Verify that the 18 ns propagation delay meets system timing requirements. Ensure the 32 mA sink current capability is sufficient for the connected load capacitance and trace characteristics in the specific circuit design.

Part Context

This part belongs to the Texas Instruments SN74ALS family of advanced low-power Schottky logic devices. The SN74ALS843 specifically addresses the need for multi-bit storage with bus isolation capabilities. It serves as a bridge between microprocessors and peripheral memory or I/O devices, enabling efficient data transfer across shared system buses without signal contention.

Replacement Considerations

The SN74ALS843DW is a documented equivalent offering identical logical functionality in an SOIC-24 surface-mount package. Verify pinout compatibility before substitution to ensure proper board layout adaptation.