Additional Information – Stability
When TS432 series is used as a shunt regulator, there are two options for selection of CL, are 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 TS432 series 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 TS432 series 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