This anomaly applies to Revision 2, build codes CAAA-D00, QEAA-D00.
It was inherited from the previous PMIC revision Engineering E.
Symptoms
LDO input voltage drops.
Conditions
LOADSW1/LDO1 or LOADSW2/LDO2 starts up in LDO mode.
Consequences
The following can occur during the LDO startup:
- The device is powered from VBUS:
- When the LDO input is connected to VSYS and VBUSINILIM0 is set to 100 mA, VSYS can drop to VBAT level and the charger can enter supplement mode.
- When BUCK is used in forced PFM mode and BUCK output is used as the LDO input, the voltage on BUCK output might drop more than 1 V.
- The device is powered from VBAT:
- When the LDO input is connected to VSYS and VBAT is less than VOUT + VDROP_OUT + 300 mV, BUCK converter can go to drop-out and out of regulation.
- When BUCK is used in forced PFM mode and BUCK output is used as the LDO input, the voltage on BUCK output might drop more than 1 V.
Note: Starting up both LDOs within 200 μs of each other increases the
impact of the described consequences.
Workaround
Apply the appropriate workaround:
- When the device is powered from VBUS and LDO input is connected to VSYS, increase the VBUSINILIM0 limit to 500 mA or higher before enabling LDO to reduce the voltage drop.
- When BUCK output is used as the LDO input, use BUCK in PWM mode or automatic mode.
- Avoid starting up both LDOs within 200 μs of each other.