ZHCSLQ5D October 2007 – August 2020 LM5067
PRODUCTION DATA
The series pass MOSFET (Q1) is enabled when the input supply voltage (VSYS) is within the operating range defined by the programmable undervoltage lockout (UVLO) and overvoltage lock-out (OVLO) levels. Typically the OVLO level at VSYS is set with a resistor divider (R1-R3) as shown in Figure 9-1. If VSYS raises the OVLO pin voltage more than 2.5 V above VEE Q1 is switched off by the 2.2 mA pull-down current at the GATE pin, denying power to the load. When the OVLO pin is above 2.5 V, the internal 22 µA current source at OVLO is switched on, raising the voltage at OVLO and providing threshold hysteresis. When the voltage at the OVLO pin is reduced below 2.5 V the 22 µA current source is switched off, and Q1 is enabled. See Figure 9-1 for a procedure to calculate the threshold setting resistor values.