npm1300

[30] BUCK: BUCK output voltage accuracy is outside specification

This anomaly applies to Engineering C, build codes QEAA-BA0, CAAA-BA0, QEAA-BC0.

Symptoms

BUCK output voltage exhibits a negative transient.

Conditions

One or both of the following conditions are present:
  • Data is transmitted on TWI lines.
  • BUCK is transitioning mode from PWM to Hysteretic when BUCKS are in auto mode and nPM1300 supplied only by VBAT. Resulting transient duration depends on load. Lower loads exhibit a longer transient.

Consequences

BUCK output voltage transient exceeds specification of ±5%. BUCK output voltage reduces by approximately 8%.

Workaround

If data is being transmitted on TWI lines, avoid TWI activity when output voltage accuracy is critical. Reducing driver strength of TWI reduces inaccuracy.

If BUCK is transitioning mode from PWM to Hysteretic when BUCKS are in auto mode and nPM1300 supplied only by VBAT, use forced PWM or Hysteric mode when output voltage accuracy is critical.

Parent topic: New and inherited anomalies