SN74HC251DE4

Overview

The SN74HC251DE4 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 a body size of 9.90 mm by 3.90 mm. Typical propagation delay is 9 ns, with maximum input current of 1 μA and typical power dissipation capacitance of 70 pF.

Feature Summary

• Features three-state outputs that interface directly with system buses or drive up to 15 LSTTL loads.
• Provides complementary true and inverted data outputs controlled by the output-enable input.
• Performs parallel-to-serial conversion using full binary decoding for 1-of-8 data selection.

Applications

• Bus-organized system data line interfacing
• Parallel-to-serial data conversion
• Strobe-controlled data routing

Procurement Notes

Verify the specific ordering suffix 'E4' against the manufacturer's current product folder to confirm active status and lead finish specifications. Confirm the package type matches the required board layout dimensions. Check for any recent Product Change Notifications regarding availability or material composition updates before finalizing procurement plans.

Selection Notes

Select this component when a standard multiplexer requires high-impedance bus isolation capabilities. Ensure the design accommodates the specified 2 V to 6 V supply voltage range. Verify that the 16-pin SOIC footprint aligns with the PCB design constraints. Consider the typical 9 ns propagation delay for timing-sensitive applications.

Part Context

This part belongs to the Texas Instruments SNx4HC251 family of data selectors. It serves as the three-state output version of the SN74HC151 multiplexer. The family includes various package options such as SSOP, PDIP, and TSSOP. The device is designed for general-purpose digital logic applications requiring efficient data routing and bus management.

Replacement Considerations

SN74HC151D (Non-three-state equivalent)

FAQ

How are the outputs controlled?

The outputs are controlled by the output-enable (OE) input. When OE is high, both outputs are disabled (high-impedance state). When OE is low, the selected data input drives the outputs.

What happens if inputs are left floating?

All unused inputs must be connected to a logic high or logic low voltage. Leaving inputs floating results in undefined operational states and may increase power consumption.