SN74HC251NSR

Overview

The SN74HC251NSR is a data selector/multiplexer from the Texas Instruments SNx4HC251 family, featuring full binary decoding to select one of eight data sources. It provides strobe-controlled complementary 3-state outputs suitable for bus-organized systems. The device operates within a wide voltage range of 2 V to 6 V and supports an operating temperature range of -40°C to 85°C. Key electrical characteristics include a maximum supply current (ICC) of 80 μA, typical propagation delay (tpd) of 9 ns, and output drive capability of ±6 mA at 5 V. It is housed in a 16-pin NS (SOP) package.

Feature Summary

• Features high-current 3-state outputs that interface directly with system buses or drive up to 15 LSTTL loads.
• Provides complementary true and inverted outputs controlled by a strobe input for efficient data routing.
• Delivers low power consumption with a maximum ICC of 80 μA and low input current of 1 μA max.
• Performs parallel-to-serial conversion and functions as a high-speed data selector.

Applications

• Data source selection and routing in digital systems.
• Parallel-to-serial data conversion.
• Demultiplexing applications requiring bus-compatible outputs.
• High-speed logic operations in industrial and consumer electronics.

Procurement Notes

Verify the specific ordering suffix 'SR' corresponds to the tape-and-reel packaging configuration on the official Texas Instruments orderable addendum. Confirm the active production status and RoHS compliance details for this specific variant before procurement. Ensure the SOP package dimensions match the design constraints. Check for any recent product change notifications regarding material or lead finish updates.

Selection Notes

Select the SN74HC251NSR when a strobed 8-to-1 multiplexer with 3-state outputs is required for bus interfacing. Choose this part over the non-3-state SN74HC151 if bidirectional bus communication is needed. Consider the 2 V to 6 V operating range for compatibility with various logic families. Verify that the -40°C to 85°C commercial temperature range meets the application environment requirements.

Part Context

The SN74HC251NSR belongs to the SNx4HC251 series of data selectors/multiplexers manufactured by Texas Instruments. This series is the 3-state version of the SN74HC151. The 'NS' designation indicates a 16-pin Small Outline Package (SOP), while 'SR' denotes the reel packaging format. It is part of the broader HC (High-speed CMOS) logic family designed for general-purpose digital applications.

Replacement Considerations

SN74HC251DR: Same function in SOIC package. SN74HC251DBR: Same function in SSOP package. SN74HC251PWR: Same function in TSSOP package. SN74HC151: Non-3-state equivalent without complementary outputs.