LM385Z-1.2/LFT4

Overview

The LM385Z-1.2/LFT4 is a micropower shunt voltage reference diode manufactured by National Semiconductor, now part of Texas Instruments. It provides a stable reference voltage of 1.235 V with an initial accuracy of ±1%. The device operates within a current range of 10 μA to 20 mA and features a low dynamic impedance of less than 1 Ω. Designed for commercial applications, it functions reliably between 0°C and +70°C. The component utilizes a TO-92 plastic package with three pins, offering a compact solution for precision analog circuits requiring a fixed low-voltage reference.

Feature Summary

• Provides a precise 1.235 V reference output suitable for high-accuracy analog signal processing
• Operates efficiently at microampere levels, enabling extended battery life in portable devices
• Features low dynamic impedance to maintain stability under varying load conditions

Applications

• Precision analog-to-digital converter (ADC) reference sources
• Battery-powered instrumentation and measurement systems
• Temperature sensing circuits utilizing bandgap characteristics

Procurement Notes

Verify the specific suffix LFT4 against official datasheets to confirm pinout and packaging details, as variations exist across manufacturers. Ensure the source document explicitly lists this exact part number to avoid confusion with standard LM385Z-1.2 variants. Confirm RoHS compliance status if required for your manufacturing process, as older National Semiconductor parts may have different environmental certifications.

Selection Notes

Select this component when a fixed 1.2V reference is needed with minimal quiescent current consumption. It is ideal for designs where space is limited due to the TO-92 form factor. Consider the ±1% initial accuracy and temperature coefficient requirements; if tighter tolerance or lower drift is necessary, explore the LM385B series or adjustable references like the TLV431.

Part Context

This device belongs to the LM385 family of micropower voltage references, which are widely used in industrial and consumer electronics. The LM385 series offers both 1.2V and 2.5V options, providing designers with flexible reference solutions. As a legacy product from National Semiconductor, it remains supported through Texas Instruments, ensuring long-term availability for established electronic designs.

Replacement Considerations

Publicly confirmed substitutes include the LM385B-1.2 for improved accuracy and the LM285-1.2 for equivalent performance. Surface-mount alternatives such as the LM385M-1.2 offer similar electrical characteristics in an SOIC package.