10 Replies Latest reply on Sep 17, 2020 6:41 AM by SyPU_4767001

    S6AE102A Overshoot on VOUT_LDO

    SyPU_4767001

      My application is almost the design given on page 28 of datasheet, modified as follows:

      CIN0 open, INT = AGND, STBY_LDO = VINT, ENA_LDO = VINT.

      R1=0, R2=6.8M, R3=10M => VoutH=5.2V VoutL=3.05V

      R4=10M, R5=6.2M => VoutLDO=3V

      VBAT= 3V, VoutLDO load = 120uA

      When VSTORE2 is low enough to switch from VDD to VBAT mode, I can observe an overshoot of 450mV on VoutLDO when Vout2 is switched from VABT to VSTORE1. What is very strange is that the voltage raises for roughly 50us, then decrease to nominal voltage in 8ms. This is much longer than any time constant given by the R and C of the schematic.

      When I raise VBAT, I can observe a second overshoot when Vout2 is switched from lower value of VSTORE1 (V=VoutL) to VBAT. The first overshhoot disappears when VBAT is 5.5V. The overshoot value seems dependant on the dV of VIN_LDO