LM385BYZ-1.2

Overview

The LM385BYZ-1.2 is a micropower two-terminal bandgap voltage regulator diode manufactured by National Semiconductor, now part of Texas Instruments. It provides a precise reference voltage of 1.235 V and operates within a wide current range from 10 µA to 20 mA. The device features exceptionally low dynamic impedance of 1.0 Ω and tight initial tolerance grades, including the B grade at 1.0%. Designed for commercial applications, it functions reliably between 0°C and +70°C. Packaged in the low-cost TO-226AA plastic case (TO-92), it offers stable operation over time and temperature with low noise characteristics.

Feature Summary

• Micropower two-terminal bandgap voltage regulation
• Extremely low dynamic impedance for excellent stability
• Wide operating current range suitable for battery life extension
• Tight voltage tolerance achieved through on-chip trimming

Applications

• Portable instrumentation requiring extended battery life
• Precision current source circuits
• Low-power regulators and analog circuitry
• Industrial isolation amplifier biasing

Procurement Notes

Verify the specific suffix 'B' indicates the 1.0% initial tolerance grade rather than standard grades. Confirm the manufacturer designation as National Semiconductor or Texas Instruments depending on the production era. Ensure the package matches the TO-226AA/TO-92 specification. Check RoHS compliance status as older National Semiconductor parts may not be compliant.

Selection Notes

Select this component when a fixed 1.235 V reference is required with high precision (1.0% tolerance). It is suitable for designs needing operation down to 10 µA to maximize battery efficiency. Compare against the LM285 variant if industrial temperature ranges (-40°C to +85°C) are necessary instead of the commercial range.

Part Context

This device belongs to the LM285/LM385 series of micropower voltage references. The LM385 series is rated for commercial temperatures (0°C to +70°C), while the LM285 covers industrial temperatures. The 'B' suffix denotes a tighter 1.0% initial accuracy compared to other grades like 1.5%, 2.0%, or 3.0%. These bipolar, two-terminal devices serve as cost-effective alternatives to more complex reference ICs.

Replacement Considerations

LM385BZ-1.2/NOPB: Direct replacement with updated manufacturing details.

FAQ

What is the minimum operating current for the LM385BYZ-1.2?

The device is designed to operate over a wide current range starting from 10 µA.

How does the 'B' suffix affect the performance?

The 'B' suffix indicates a 1.0% initial voltage tolerance, offering higher precision than standard grades.