SN74ALS259DR

Overview

The SN74ALS259DR is an 8-bit addressable latch manufactured by Texas Instruments in the ALS logic series. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature range of 0°C to 70°C. The device features asynchronous parallel clear, active-high decoding capabilities, and an enable input for expansion. It is housed in a 16-pin Small-Outline (D) package. Electrical characteristics include a low-level output current of up to 8 mA and high-level output current of -0.4 mA at 4.5 V.

Feature Summary

• Provides four distinct functional modes including addressable latch, memory, demultiplexer, and clear operations.
• Features an asynchronous parallel clear function that forces all outputs low regardless of other inputs.
• Includes an enable/disable input to simplify system expansion and prevent erroneous data entry during address changes.

Applications

• General-purpose storage applications in digital systems
• Working registers and serial-holding registers
• Active-high decoders or demultiplexers

Procurement Notes

Verify the specific ordering suffix 'DR' corresponds to the SOIC-16 tape-and-reel packaging configuration. Confirm the component status as Active Production on official manufacturer documentation before procurement. Ensure the selected variant meets the required commercial temperature range specifications for your application environment.

Selection Notes

Select this component when designing systems requiring 8-bit addressable latching with active-high outputs. Consider the ALS series performance characteristics regarding propagation delay and power consumption relative to standard TTL alternatives. Verify compatibility with the system's voltage levels and timing requirements for setup and hold times.

Part Context

This part belongs to the Texas Instruments SN74ALS259 family of 8-bit addressable latches. It is the commercial grade version characterized for operation from 0°C to 70°C, distinct from the military grade SN54ALS259 which supports -55°C to 125°C. The 'DR' suffix specifically denotes the plastic small-outline package delivered in a tape and reel format.

Replacement Considerations

SN74ALS259N

FAQ

What are the four operational modes of the SN74ALS259?

The device supports addressable latch mode, memory mode, 1-of-8 decoding/demultiplexing mode, and clear mode, selectable via the CLR and G inputs.

How does the enable input affect operation?

Holding the enable input high prevents data from entering the latches, ensuring no erroneous data is written while address lines are changing.