ADR1399 Precision Shunt Reference

ADI's ADR1399 precision shunt reference features excellent temperature stability over a wide range of voltage, temperature, and quiescent current conditions. A temperature stabilizing loop is incorporated with the active Zener on a monolithic substrate, which nearly eliminates changes in voltage with temperature. The subsurface Zener circuit is fully specified at a quiescent current I_REF of 3 mA and offers minimal noise and excellent long-term stability. The ADR1399 offers much lower output dynamic impedance than the LM399, reducing the effects of shunt resistor (R_SHUNT) and the supply voltage variation on the reference output.

The ADR1399H-EBZ allows the evaluation of the ADR1399KHZ, ultra-stable 7.05 V shunt voltage reference in a 4-lead TO-46 package. The DUT is elevated on its leads in order to increase the thermal isolation from the 4-layer board ground planes.

Isolated power means that the reference output is effectively floated, removing the likelihood of ground loops. The isolation is bridged only by a 1 Meg resistor. Power may be supplied via the USB-C® cable, or 5 V may be applied to VUSB, or power may be back driven onto the regulator outputs at VPRE or V+. The ultra-stable 7.05 V is brought out to both banana jacks and an edge-mounted SMA connector.