LM399H

Overview

The LM399H is a precision shunt voltage reference manufactured by Analog Devices Inc. It features a guaranteed output voltage of 6.95V with an initial tolerance of 2%. The device incorporates a stabilizing heater and active Zener on a monolithic substrate to achieve excellent temperature stability, offering a guaranteed temperature coefficient of 0.5ppm/°C. It operates within a current range of 0.5mA to 10mA and provides a maximum dynamic impedance of 1Ω. The component is housed in a 4-lead TO-46 metal can package and supports an operating temperature range from 0°C to +70°C.

Feature Summary

• Integrated stabilizing heater and active Zener for high thermal stability
• Low noise performance suitable for precision applications
• Wide operating current range from 0.5mA to 10mA
• Available in a 4-lead TO-46 metal can package

Applications

• Digital voltmeters
• Precision calibration equipment
• Laboratory measurement equipment
• Industrial monitor/control instruments
• High accuracy data converters

Procurement Notes

Verify the specific suffix (e.g., #PBF) against the manufacturer's ordering information to confirm lead-free finish status and packaging type. Ensure the selected variant matches the required operating temperature range, as the LM399H is specified for 0°C to +70°C. Cross-reference the datasheet revision history for any updates to package dimensions or electrical characteristics before finalizing procurement specifications.

Selection Notes

Select the LM399H when high long-term stability and low temperature drift are critical requirements. The integrated heater design eliminates the need for external temperature control circuits. Consider the 4-lead TO-46 package for through-hole mounting. Verify that the application circuit can support the necessary heater supply voltage and current to maintain the stabilized junction temperature.

Part Context

The LM399H belongs to the LM199/LM399 family of precision references. While the LM199 variants cover a wider -55°C to 125°C range, the LM399H is optimized for commercial temperatures (0°C to 70°C). Both share the same core architecture featuring a subsurface Zener and internal heater for superior stability compared to standard zener diodes.

Replacement Considerations

Consult manufacturer marketing for parts specified with wider operating temperature ranges if environmental conditions exceed 0°C to 70°C. The LT1021 is listed as a related part with industry-standard pinout but different temperature specifications.