STATUS

UVLO

OVP

TIMER

GND

EN

OUT

SENSE

GATE

VIN

LM5060

EN

R8

R10

R11

Q1

C1

R4

GND

GND

nPGD

High = Fault, Low= OK

High = On, Low= Off

R9

LM5060

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SNVS628F – OCTOBER 2009 – REVISED APRIL 2013

Figure 21. Basic Application Circuit

Functional Description

The LM5060 is designed to drive an external high-side N-channel MOSFET. Over-Current protection is

implemented by sensing the voltage drop across the MOSFET. When an adjustable voltage drop threshold is

exceeded, and an adjustable time period has elapsed, the MOSFET is disabled. Over-Voltage Protection (OVP)

and Under-Voltage Lock-Out (UVLO) monitoring of the input line is also provided. A low state on the enable pin

will turn off the N-channel MOSFET and switch the LM5060 into a very low quiescent current off state. An active

low power good output pin is provided to report the status of the N-channel MOSFET. The waiting time before

the MOSFET is turned off after a fault condition is detected can be adjusted with an external timer capacitor.

Since the LM5060 uses a constant current source to charge the gate of the external N-channel MOSFET, the

output voltage rise time can be adjusted by adding external gate capacitance. This is useful when starting up into

large capacitive loads.

POWER-UP SEQUENCE

The basic application circuit is shown in Figure 21 and a normal start-up sequence is shown in Figure 22. Start-

capacitor is charged with a 6 µA (typical) current source while the gate of the external N-channel MOSFET is

charged through the GATE pin by a 24 µA (typical) current source.

timer capacitor is quickly discharged to 0.3V, and begins charging the timer capacitor with a11 µA current

source.

pin. The SENSE pin voltage is user programmed to be lower than the input supply voltage by selecting a suitable

sense resistor value. When the OUT pin voltage exceeds the voltage at the SENSE pin, the nPGD pin is

asserted low (i.e. no fault) and the timer capacitor is discharged.

STATUS CONDITIONS

Output responses of the LM5060 to various input conditions is shown in Table 1. The input parameters include

Enable (EN), Under-Voltage Lock-Out (UVLO), Over-Voltage Protection (OVP), input voltage (VIN), Start-Up

GATE charge current, the TIMER capacitor charge (or discharge) current, the GATE discharge current if the

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