SN74HC251D

Overview

The SN74HC251D is a data selector/multiplexer with 3-state outputs in a 16-pin SOIC package. It features full binary decoding to select one of eight data sources and provides strobe-controlled complementary outputs. The device operates within a supply voltage range of 2 V to 6 V, with an operating temperature range of -40°C to 85°C. Typical propagation delay is 9 ns at 5 V. Outputs can drive up to 15 LSTTL loads or interface directly with system buses.

Feature Summary

• Provides parallel-to-serial conversion capabilities through full binary decoding of eight input lines.
• Features complementary true and inverted outputs controlled by a strobe signal for bus interfacing.
• Supports wide operating voltage ranges suitable for various logic families.

Applications

• Bus-oriented systems requiring data selection
• Parallel-to-serial data conversion circuits
• Strobe-controlled multiplexing applications

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current Package Option Addendum to confirm active production status and lead finish specifications. Ensure the selected variant matches the required thermal resistance and moisture sensitivity level for the intended assembly process. Cross-reference the datasheet revision history for any functional updates.

Selection Notes

Select this component when a high-current 3-state output is required to drive system buses or multiple loads. Consider the HC series performance characteristics regarding propagation delay and power consumption relative to other logic families. Verify that the SOIC package dimensions align with the available board space and thermal management requirements.

Part Context

This part belongs to the SNx4HC251 family of data selectors/multiplexers. It serves as the 3-state output version of the SN74HC151. The 'D' suffix specifically denotes the 16-pin Small Outline Integrated Circuit (SOIC) package format, distinguishing it from SSOP, PDIP, or TSSOP variants within the same logical family.

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 3-state outputs; when OE is high, all outputs are disabled (high-impedance state).