TS432I

Adjustable Precision Shunt Regulator

3/10

Version: C14

Test Circuits

Figure 3: Off-State Current

Additional Information – Stability

stability:

A)

No load capacitance across the device, decouple at the load.

B)

Large capacitance across the device, optional decoupling at the load.

The reason for this is that TS432AI/432BI exhibits instability with capacitances in the range of 10nF to 1µF (approx.) at light cathode

current up to 3mA(typ). The device is less stable the lower the cathode voltage has been set for. Therefore while the device will be

perfectly stable operating at a cathode current of 10mA (approx.) with a 0.1µF capacitor across it, it will oscillate transiently during

start up as the cathode current passes through the instability region. Select a very low capacitance, or alternatively a high

capacitance (10µF) will avoid this issue altogether. Since the user will probably wish to have local decoupling at the load anyway,

the most cost effective method is to use no capacitance at all directly across the device. PCB trace/via resistance and inductance

prevent the local load decoupling from causing the oscillation during the transient start up phase.

Note: if the TS432AI/432BI is located right at the load, so the load decoupling capacitor is directly across it, then this capacitor will

have to be

≤1nF or ≥10µF.

Applications Examples

Figure 4: Voltage Monitor

Figure 5: Output Control for Three Terminal

Fixed Regulator