LM285BXM-1.2/NOPB

Overview

The LM285BXM-1.2/NOPB is a micropower voltage reference diode manufactured by Texas Instruments, formerly National Semiconductor. It provides a fixed output voltage of 1.235V with a tight tolerance of ±1%. The device operates within a temperature range of -40°C to +85°C and features a low temperature coefficient of 30ppm/°C. Key electrical specifications include a maximum cathode current of 10 µA and an output current capability of 20 mA. Noise performance is specified at 60µVrms over the 10Hz to 10kHz frequency band. It is housed in an 8-pin SOIC package.

Feature Summary

• Provides a stable fixed reference voltage of 1.235V suitable for precision applications
• Operates with extremely low quiescent current consumption for power-sensitive designs
• Maintains high accuracy with ±1% initial tolerance across the industrial temperature range

Applications

• Portable battery-powered instrumentation requiring low standby current
• Data acquisition systems needing precise analog-to-digital conversion references
• Microprocessor supervisory circuits and window comparators

Procurement Notes

Verify the component origin carefully, as the part number indicates National Semiconductor branding but is currently produced and supported by Texas Instruments. Confirm the suffix NOPB denotes lead-free and RoHS compliance. Ensure the specific batch matches the required operating temperature range of -40°C to +85°C for your application environment. Check for any recent product change notices regarding packaging or material composition updates from the manufacturer.

Selection Notes

Select this component when a fixed 1.235V reference is required with minimal power draw. The ±1% tolerance offers higher precision than standard adjustable variants like the LM285M. Consider the 8-SOIC package constraints for PCB layout. This fixed version eliminates external resistor networks needed for adjustable references, simplifying circuit design while maintaining low noise characteristics essential for sensitive analog front ends.

Part Context

This device belongs to the LM285 family of micropower shunt voltage references. Unlike the adjustable LM285 series which requires external resistors to set voltage, this variant has the internal reference network permanently configured for 1.235V. It shares the same low-power architecture and thermal stability characteristics as other members of the family but offers a specific fixed output level optimized for low-voltage logic and sensor biasing applications.

Replacement Considerations

Direct substitutes include the LM285BXM-1.2 without the NOPB suffix if non-RoHS compliance is acceptable. For adjustable versions, the LM285MX/NOPB can be used with external resistors, though this changes the circuit topology. Ensure pinout compatibility with the 8-SOIC package when swapping with other manufacturers' equivalents.