LM399AH

Overview

The LM399AH is a precision shunt voltage reference manufactured by Analog Devices Inc., housed in a 4-lead TO-46 metal can package. It provides a fixed output voltage of 6.95V with an initial tolerance of ±0.17%. The device operates within a temperature range of 0°C to 70°C and features a maximum dynamic impedance of 1Ω. RMS noise is guaranteed at a maximum of 20µV over the 10Hz to 10kHz frequency band.

Feature Summary

• Incorporates a stabilizing heater integrated with an active Zener on a monolithic substrate to minimize voltage changes across varying temperatures.
• Utilizes a subsurface Zener structure that ensures minimal noise generation and excellent long-term stability.
• Designed for high precision applications requiring stable references under wide operating current conditions.

Applications

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

Procurement Notes

Verify the specific suffix against official documentation, as ordering codes may indicate variations in packaging or lead finish. Confirm the component status is active for new designs. Ensure the selected variant matches the required thermal shield dimensions and pin configuration for the target application circuit.

Selection Notes

Select this component when superior temperature stability is critical compared to standard Zener diodes. The internal heater requires a supply voltage between 9V and 40V. Consider the warm-up time and initial surge current requirements during power-on. Verify that the operating environment stays within the specified 0°C to 70°C range for guaranteed performance.

Part Context

This part belongs to the LM399 family of precision references, which are designed to replace standard cells in calibration systems. The 'A' designation typically denotes tighter initial tolerance specifications compared to the base model. The device is distinct from the obsolete LM199 series, which supports a wider temperature range down to -55°C.

Replacement Considerations

Consult manufacturer marketing for parts specified with wider operating temperature ranges if the application exceeds 70°C. No direct public substitute part numbers are confirmed in the provided datasheet text.