LTC4224-1/LTC4224-2

5

422412fa

PIN FUNCTIONS

SENSE1, SENSE2 (Pins 1,10): Current Sense Input. Con-

nect this pin to an external sense resistor. The current limit

and SENSEn to 25mV. An Electronic Circuit Breaker (ECB)

is active during current limiting and trips after 5ms. To

Input. An undervoltage lockout circuit disables the part

lower supply is disabled until it exceeds 0.8V.

GATE1, GATE2 (Pins 3, 8): Gate Drive for External N-channel

MOSFET. A charge pump sources 10μA from GATE to turn

on the external MOSFET. An internal clamp limits the gate

turn-off, a 1.5mA pulldown current discharges GATE to

ground. During short-circuits, a 125mA pulldown current

is activated to discharge GATE to ground.

FAULT (Pin 4): Fault Status Output. Open-drain output

nal resistor. It is pulled low when the ECB trips due to an

overcurrent condition at either supply. This pin may be

left open if unused.

ON1, ON2 (Pins 5, 6): On Control Input. A falling edge

turns on the external N-channel MOSFET and a rising edge

turns it off. A low to high transition on this pin resets an

ECB fault for the corresponding channel. Internally pulled

GND (Pin 7): Device Ground.

Exposed Pad (DFN Package Only): Exposed Pad may be

left open or connected to device ground.

FUNCTIONAL DIAGRAM

CHARGE

PUMP

422412 FD

0.8V

0.8V

2.4V

–

+

–

+

–

+

–

+

CHARGE

PUMP

–

+

GATE

PULLDOWN

LOGIC

CONTROL

GATE

PULLDOWN

0.8V

–

+

0.8V

10μA

10μA

GATE1

GATE2

ON1

FAULT

ON2

SENSE2

SENSE1

GND

ACL1

ACL2

10μA

10μA

5.5V

5.5V

ON2

ON1

ECB1

ECB2

25mV

25mV