SN74LS148N

Overview

The SN74LS148N is an 8-line-to-3-line priority encoder manufactured by Texas Instruments. It operates within a supply voltage range of 4.75V to 5.25V, with a typical operating voltage of 5V. The device features a propagation delay of 19ns and supports a maximum clock frequency of 35MHz. Power dissipation is rated at 500mW. It utilizes a 16-pin PDIP package and functions across a temperature range of 0°C to +70°C.

Feature Summary

• Provides active-low encoding for eight input lines into three-bit binary outputs
• Includes dedicated Enable Input (EI) and Enable Output (EO) pins for cascading multiple units without external logic
• Features buffered inputs to maintain standardized loading characteristics across the series

Applications

• Expanding 8-line encoders to form 16-line to 4-line priority encoding systems
• Converting octal data signals into binary codes for digital processing
• Generating specific control codes from multiple active input sources

Procurement Notes

Verify that the component matches the SN74LS148N designation specifically, as suffixes may indicate different packaging or environmental compliance levels. Confirm the manufacturer is Texas Instruments to ensure compatibility with specified electrical parameters. Check for RoHS compliance status if required by project regulations. Ensure the package type corresponds to the design requirements, typically 16-pin PDIP for this part number.

Selection Notes

Select this component when low-power Schottky TTL performance is required for priority encoding tasks. It is suitable for designs needing cascading capabilities via EI/EO pins. Consider the 19ns propagation delay and 35MHz frequency limits against system timing requirements. Ensure the 4.75V to 5.25V supply voltage aligns with the target circuit's power distribution.

Part Context

This device belongs to the Texas Instruments 74LS series of logic integrated circuits. It is functionally related to other priority encoders like the SN74LS147 but offers eight inputs instead of ten. The SN74LS148N is distinct from high-speed CMOS variants such as the SN74HC148, which operate over a wider voltage range. It serves as a fundamental building block in digital logic systems requiring efficient signal prioritization.

Replacement Considerations

SN74LS148NE4 is a verified equivalent part number from Texas Instruments.