SN74LS148DG4

Overview

The SN74LS148DG4 is an octal priority encoder manufactured by Texas Instruments, belonging to the 74LS logic family. It converts eight active-low data inputs into a three-bit binary code with inverted outputs. The device features dedicated Enable Input (EI), Group Signal (GS), and Enable Output (EO) pins to facilitate cascading multiple units for expanded encoding capabilities without external logic. It operates on a single 5V power supply within a specified voltage range of 4.75V to 5.25V. The component is housed in a 16-pin SOIC package and supports surface-mount installation.

Feature Summary

• Implements priority encoding where the highest-order active input determines the output code, ignoring lower-priority signals.
• Provides internal expansion capability through dedicated enable control pins for connecting multiple encoders.
• Features buffered inputs to maintain standardized loading characteristics across the logic series.

Applications

• Converting keyboard matrix scan codes into binary addresses for microprocessor systems.
• Interrupt request prioritization in digital control circuits.
• Octal-to-binary code conversion in data acquisition systems.

Procurement Notes

Verify that the ordering suffix 'G4' confirms compliance with RoHS 3 standards and lead-free manufacturing requirements as per Texas Instruments specifications. Ensure the selected package variant matches the required surface-mount footprint dimensions. Confirm availability status directly with authorized distributors, as production lifecycles for legacy LS series components may vary. Cross-reference the manufacturer part number against official TI documentation to validate authenticity and specific revision levels before procurement.

Selection Notes

Select this component when designing systems requiring priority-based signal encoding using standard TTL-compatible logic levels. It is suitable for applications needing simple, low-power octal-to-binary conversion with minimal external circuitry. Consider the 74LS series characteristics regarding speed and power dissipation relative to system requirements. Verify that the operating temperature range meets the environmental conditions of the intended deployment scenario.

Part Context

This part belongs to the widely used 74LS (Low-power Schottky) logic family, known for balancing speed and power consumption. The SN74LS148 is a standard octal priority encoder, often paired with decoders like the SN74LS145 in complete decoding architectures. Its design allows for straightforward integration into legacy and modern digital systems requiring reliable binary translation of multiple input lines.

Replacement Considerations

Compatible substitutes include the SN74LS148DR and SN74LS148N. These variants offer identical logical functionality but differ in packaging or reel configuration. Verify pin compatibility and electrical specifications before substitution.