TS2431

Adjustable Precision Shunt Regulator

3/13

Version: E07

Test Circuits

Figure 3: Off-State Current

Additional Information – Stability

recommended for optional 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 TS2431/2431A/2431B exhibits instability with capacitances in the range of 10nF to 1uF

(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 0.1uF

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 (10uF) 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 TS2431/2431A/2431B is located right at the load, so the load decoupling capacitor is directly across it, then

this capacitor will have to be ≤1nF or ≥10uF.

Applications Examples

Figure 4: Voltage Monitor

Figure 5: Output Control for Three Terminal

Fixed Regulator