Other Parts Discussed in Thread: TPS7H1101A-SP
Problem:
Input voltage VIN=5.82 V, output voltage is set to 5.37 V, output current 100 mA. Rpcl=150K. If the EN input is directly connected to VIN the LDO, output voltage is correct 5.37 V. When the IC is disabled/enabled (EN pin), sometimes the output voltage drops to the stable level 5.21 V (voltage on FB input 0.585 V). Why?
Steps Needed to Recreate Problem:
Power on the PSU with LDO, EN connected via 22K resistor to the GND. LDO output voltage is 0 V.
Enable the LDO by connecting EN input to VIN. LDO output voltage is lower (5.21 V) than it was set (5.37 V).
Repeat disable/enable cycle, sometimes the output voltage is correct 5.37 V, sometimes lower 5.21 V.
Both levels are stable.
If the LDO is disabled by SS input connected to GND the output voltage after enabling is always correct 5.37 V.
Application Schematic:
