SN74ALS1645ANS

Overview

The SN74ALS1645AN is an octal bus transceiver from the Texas Instruments ALS logic series, housed in a 20-pin plastic dual in-line package (PDIP). It provides asynchronous two-way communication between data buses with noninverting logic and 3-state outputs. The device operates on a supply voltage ranging from 4.5 V to 5.5 V and supports a high-level output current of -15 mA and a low-level output current of 16 mA. Propagation delays range from 2 ns to 15 ns depending on direction and control states.

Feature Summary

• Provides asynchronous bidirectional data transmission between A and B buses controlled by a DIR input
• Features 3-state outputs that allow effective bus isolation when the OE input is disabled
• Delivers noninverting logic functionality for direct signal transfer

Applications

• Asynchronous two-way communication between data buses
• Memory and memory interface applications
• Control signals and data routing

Procurement Notes

Verify the specific ordering suffix 'AN' corresponds to the standard plastic DIP-20 package configuration. Confirm RoHS compliance status as indicated in the manufacturer's packaging addendum. Ensure the application environment remains within the specified 0°C to 70°C operating temperature range to maintain electrical characteristics.

Selection Notes

Select this component for designs requiring noninverting octal bus transceivers with 3-state outputs. Compare against the SN74ALS1640A if inverting logic is required instead. Consider the PDIP-20 package constraints for through-hole mounting versus surface-mount alternatives like the DW package.

Part Context

This part belongs to the SN74ALS164x family of octal bus transceivers. It serves as a lower-power alternative to older SN74ALS640B and SN74ALS645A devices. The ALS series utilizes advanced Schottky bipolar technology to achieve faster switching speeds while reducing power consumption compared to standard LS logic families.

Replacement Considerations

SN74ALS1640A (Inverting Logic)

FAQ

What is the difference between SN74ALS1645A and SN74ALS1640A?

The SN74ALS1645A features noninverting logic, whereas the SN74ALS1640A features inverting logic. Both share identical pinouts, package options, and electrical characteristics.

How does the OE input affect the device operation?

When the Output Enable (OE) input is high, the device enters an isolation state, effectively disconnecting the buses regardless of the DIR input level.