SN74HC251DT

Overview

The SN74HC251DT is a data selector/multiplexer featuring full binary decoding to select one of eight data sources. It provides strobe-controlled complementary three-state outputs suitable for bus-organized systems. The device operates within a supply voltage range of 2 V to 6 V and supports an operating temperature range of -40°C to 85°C. It utilizes a 16-pin SOIC package with dimensions of 9.90 mm by 3.90 mm.

Feature Summary

• Features high-current three-state outputs capable of driving up to 15 LSTTL loads or interfacing directly with system buses.
• Provides complementary true and inverted outputs controlled by a strobe input for efficient parallel-to-serial conversion.
• Designed for low power consumption with a maximum ICC of 80 μA and low input current of 1 μA max.

Applications

• Bus-oriented data routing in digital systems
• Parallel-to-serial data conversion
• Data selection from multiple sources

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation, as suffixes determine packaging type and material specifications. Confirm that the component status aligns with project requirements, noting that certain variants may be obsolete. Ensure compliance with RoHS directives and moisture sensitivity levels specified in the latest package addendum before procurement.

Selection Notes

Select this component when a single-channel multiplexer with three-state output capability is required for CMOS logic applications. Consider the wide operating voltage range and high drive strength if interfacing with TTL loads. Verify thermal resistance values relative to the PCB layout and ambient operating conditions to ensure reliable performance within the specified temperature limits.

Part Context

This part belongs to the Texas Instruments SNx4HC251 family of data selectors. It serves as the three-state output variant of the standard SN74HC151 multiplexer. The family includes various package options such as SSOP, PDIP, and TSSOP, catering to different board space and assembly requirements while maintaining consistent logical functionality across the series.

Replacement Considerations

SN74HC251DR

FAQ

How are unused inputs handled?

All unused inputs must be connected to either VCC or GND to prevent undefined operational states caused by floating voltages.

What is the function of the OE pin?

The Output Enable (OE) pin controls the three-state outputs; when OE is high, all outputs are disabled into a high-impedance state.