SLVSCV5E March 2015 – December 2024 ATL431 , ATL432
PRODUCTION DATA
To program the cathode voltage to a regulated voltage a resistive bridge must be shunted between the cathode and anode pins with the mid point tied to the reference pin. This can be seen in Figure 8-4, with R1 and R2 being the resistive bridge. The cathode/output voltage in the shunt regulator configuration can be approximated by the equation shown in Figure 8-4. The cathode voltage can be more accurately determined by taking in to account the cathode current:
For this equation to be valid, the ATL43x must be fully biased so that it has enough open-loop gain to mitigate any gain error. This can be done by meeting the Imin spec denoted in Electrical Characteristics, ATL431Ax, ATL432Ax table.