M74HC148B1R

Overview

The M74HC148B1R is an 8-to-3 line priority encoder manufactured by STMicroelectronics. It belongs to the 74HC logic series and utilizes silicon gate C2 MOS technology. The device encodes eight active-low data inputs into a three-line binary code. It features cascading capability through enable input (EI) and enable output (EO) pins, allowing octal expansion without external circuitry. The component operates within a supply voltage range of 2 V to 6 V and supports a wide operating temperature range from -55 °C to +125 °C. It is housed in a 16-DIP package with through-hole mounting.

Feature Summary

• Encodes eight active-low data lines into a three-line binary output
• Provides cascading functionality via dedicated enable input and output pins for system expansion
• Delivers high-speed performance comparable to LSTTL while maintaining low CMOS power consumption

Applications

• Octal expansion systems requiring priority encoding
• Interrupt control circuits prioritizing multiple signal sources
• Data conversion interfaces translating parallel inputs to binary outputs

Procurement Notes

Verify the specific suffix B1R against official STMicroelectronics documentation to confirm pinout compatibility and package dimensions. Confirm RoHS compliance status as manufacturing processes evolve. Check current production status, as availability may vary. Ensure the selected variant matches the required DIP-16 through-hole configuration for your PCB design.

Selection Notes

Select this component when designing systems requiring priority encoding with cascading capabilities. The HC series offers a balance of speed and power efficiency suitable for general-purpose digital logic. Verify that the 2 V to 6 V supply voltage range aligns with your system's power rails. Consider the -55 °C to +125 °C temperature range for industrial or harsh environment applications.

Part Context

The M74HC148B1R is part of the broader 74HC family of high-speed CMOS logic devices produced by STMicroelectronics. This family is known for compatibility with standard TTL logic levels while offering improved noise immunity and lower power dissipation compared to older technologies. The 148 function specifically addresses the need for efficient priority encoding in complex digital architectures.

Replacement Considerations

Direct substitutes include SN74HC148DR, SN74HC148DT, and SN74HC148NSR from Texas Instruments. These alternatives maintain functional equivalence for 8-to-3 line priority encoding applications.