SN74LS145NE4

Overview

The SN74LS145NE4 is a BCD-to-decimal decoder/driver from the Texas Instruments 74LS series. It features four binary inputs and ten active-low decoded outputs with open-collector configurations. The device operates on a single 5V supply, accepting voltage levels between 4.75V and 5.25V. It utilizes a 16-pin PDIP package for through-hole mounting. Electrical characteristics include a propagation delay of 50ns and a bandwidth of 35MHz. The component supports an operating temperature range of 0°C to 70°C and draws approximately 1mA of supply current.

Feature Summary

• Converts four-bit binary coded decimal (BCD) input signals into one-of-ten active-low decoded output selections.
• Features open-collector outputs capable of driving external loads directly without additional pull-up components.
• Provides inverted logic polarity for the decoded output states relative to the input selection.

Applications

• Driving decimal display indicators such as seven-segment readouts or lamp arrays.
• Selecting specific channels in multiplexed data acquisition systems.
• Implementing address decoding logic within digital control circuits.

Procurement Notes

Verify that the ordering suffix 'E4' confirms lead-free compliance and RoHS status. Confirm the package type matches the required PCB footprint. Check the datasheet for specific electrical limits regarding open-collector drive capabilities. Ensure the operating temperature range meets system requirements.

Selection Notes

Choose this component when active-low decoding is required for direct load interfacing. The open-collector design allows flexibility in output voltage levels via external pull-ups. Consider the 74LS series speed and power consumption trade-offs compared to standard TTL or advanced low-power alternatives.

Part Context

This part belongs to the SN54/74LS145 family of BCD-to-decimal decoders. It is functionally equivalent to the SN74LS145N but includes the E4 suffix indicating lead-free manufacturing. The device serves as a foundational logic component for translating binary codes into distinct decimal lines in legacy and industrial digital designs.

Replacement Considerations

SN74LS145N

FAQ

What is the logic state of the outputs?

The outputs are active-low, meaning the selected output line goes to a low logic state while all others remain high.

How are the outputs configured?

The outputs are open-collector, requiring external pull-up resistors to define the high voltage level and limit current.