LTC4236 datasheet(9/24 Pages) LINER

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LTC4236

4236f

For more information www.linear.com/LTC4236

pin FuncTions

HGATE: Hot Swap MOSFET Gate Drive Output. Connect

this pin to the gate of the external N-channel MOSFET for

HotSwapcontrol.Aninternal10µAcurrentsourcecharges

the MOSFET gate. An internal clamp limits the gate volt-

age to 12V above and a diode voltage below OUT. During

an undervoltage generated turn-off, a 2mA pull-down

discharges HGATE to ground. During an output short or

INTVCC undervoltage lockout, a fast 200mA pull-down

discharges HGATE to OUT.

IN1, IN2: Positive Supply Input and Ideal Diode MOSFET

Gate Drive Return. Connect this pin to the power input

side of the external ideal diode MOSFET. The 5V INTVCC

supply is generated from IN1, IN2 and OUT via an internal

diode-OR. The voltage sensed at this pin is used to control

DGATE. The gate fast pull-down current returns through

IN1 pin when DGATE1 is discharged.

INTVCC: Internal 5V Supply Decoupling Output. This pin

must have a 0.1µF or larger capacitor to GND. An external

load of less than 500µA can be connected at this pin. An

undervoltage lockout threshold of 2.2V will turn off both

MOSFETs.

IMON: Current Sense Monitoring Output. This pin voltage

is proportional to the sense voltage across the current

sense resistor with a voltage gain of 100. An internal 20k

resistor is connected from this pin to ground.

ON: ON Control Input. A rising edge above 1.235V turns

on the external Hot Swap MOSFET and a falling edge below

1.155V turns it off. Connect this pin to an external resistive

divider from SENSE+ to monitor the supply undervoltage

condition. Pulling the ON pin below 0.6V resets the fault

latch after an overcurrent fault. Tie to INTVCC if unused.

OUT: Hot Swap MOSFET Gate Drive Return. Connect this

pin to the output side of the external MOSFET. The gate

fast pull-down current returns through this pin when

HGATE is discharged.

PWRGD: Power Status Output. Output that pulls low when

the FB pin rises above 1.235V and the MOSFET gate drive

between HGATE and OUT exceeds 4.2V. Otherwise it is

pulled high by a 10µA current source to a diode below

INTVCC. It may be pulled above INTVCC using an external

pull-up. Leave open if unused.

REG: Internal Regulated Supply for Current Sense Ampli-

fier. A 0.1µF or larger capacitor should be tied from REG to

SENSE+. This pin is not designed to drive external circuits.

SENSE+: Positive Current Sense Input. Connect this pin

to the diode-OR output of the external ideal diode MOS-

FETs and input of the current sense resistor. The voltage

sensed at this pin is used for monitoring the current limit

and also to control DGATE for forward voltage regulation

and reverse turn-off. This pin has an undervoltage lockout

threshold of 1.9V that will turn off the Hot Swap MOSFET.

SENSE–: Negative Current Sense Input. Connect this pin

to the output of the current sense resistor. The current

limit circuit controls HGATE to limit the voltage between

SENSE+ and SENSE– to 25mV or less depending on the

voltage at the FB pin.

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