LM385BXMX-2.5

Overview

The LM385BXMX-2.5 is a micropower shunt voltage reference manufactured by National Semiconductor, now part of Texas Instruments. It provides a stable 2.5V output with a typical tolerance of ±1% or ±2%. The device operates within a current range of 75µA to 20mA and features a low temperature coefficient of 40ppm/°C. Designed for surface-mount applications, it utilizes an 8-SOIC package. The component supports an operating temperature range from -40°C to +85°C, ensuring reliability in commercial and industrial environments.

Feature Summary

• Provides precise 2.5V reference voltage with tight initial accuracy
• Operates efficiently at very low quiescent currents starting from 75µA
• Maintains stability across wide temperature variations with low drift
• Suitable for space-constrained designs using compact surface-mount packaging

Applications

• Portable battery-powered instrumentation requiring low power consumption
• Data acquisition systems needing stable analog reference voltages
• Microprocessor supply monitoring circuits
• Digital-to-analog converter (DAC) reference inputs

Procurement Notes

Verify the manufacturer designation as National Semiconductor or Texas Instruments, as the company was acquired. Confirm the suffix 'BMX' indicates the specific grade and tape-and-reel packaging. Ensure the 8-SOIC footprint matches your PCB design. Check for RoHS compliance status depending on production date, as older batches may differ. Validate the 2.5V nominal output against your circuit requirements.

Selection Notes

Select this component when a fixed 2.5V reference is required with higher precision than standard zener diodes. Consider the 75µA minimum operating current; ensure the load draws sufficient current to maintain regulation. Compare the 40ppm/°C temperature coefficient against application thermal stability needs. Evaluate the 8-SOIC package size relative to available board space compared to TO-92 alternatives.

Part Context

The LM385 series belongs to a family of adjustable micropower voltage references originally developed by National Semiconductor. These devices function similarly to zener diodes but offer superior performance in terms of noise, temperature stability, and current efficiency. The LM385 is widely used in legacy and modern electronic designs where a reliable, low-cost reference voltage is essential for analog signal processing.

Replacement Considerations

LM385-2.5/NOPB: Direct replacement with updated manufacturing specifications. LM385MX-2.5: Compatible variant with similar electrical characteristics. LM385Z-2.5: Alternative package option if through-hole mounting is preferred.