SNVS628H October 2009 – December 2019 LM5060
PRODUCTION DATA.
A charge pump provides bias voltage above the input and output voltage to enhance the N-channel MOSFET gate. When the system voltage is initially applied and both EN and UVLO are above their respective thresholds, the GATE pin is charged by the 24-µA (typical) current source. During normal operating conditions, the GATE pin voltage is clamped to approximately 16.8 V above the OUT pin (i.e. VGS) by an internal zener.
When either the UVLO input or the EN input is low, or when VIN is below the Power-On Reset voltage of 5.10 V (typical), the GATE pin is discharged with a 2.2 mA (typical) current sink.
When the timer capacitor is charged up to the VTMRH threshold (typically 2 V) a fault condition is indicated and the gate of the external N-Channel MOSFET is discharged at a 80 mA (typical) rate. Additionally, when the OVP pin voltage is higher than the OVPTH threshold (typically 2 V) a fault is indicated and the gate of the external N-Channel MOSFET is discharged at the same 80 mA (typical) rate.