SNVSCR4A July 2024 – October 2024 TLA431 , TLA432
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 9-1, with R1 & R2 being the resistive bridge. The cathode/output voltage in the shunt regulator configuration can be approximated by the equation shown in Figure 9-1. The cathode voltage can be more accuratel determined by taking in to account the cathode current:
Vo=(1+R1/R2)*VREF-IREF*R1
For this equation to be valid, TLA431 must be fully biased so that the TLA431 has enough open loop gain to mitigate any gain error. This can be done by meeting the Imin spec denoted in Electrical Characteristics.