LX2750

Microsemi

Analog Mixed Signal Group

5

Rev. 1.0a

07/14/10

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

PIN DESCRIPTIONS

PIN SYMBOL

PIN DESCRIPTION

This pin is internal 5V regulator output and supplies the internal 5V bias circuit. A high

freq 1uF ceramic capacitor is recommended to connect this pin to ground.

This pin supplies voltage to high side FET driver. A high freq minimum 0.1uF ceramic

capacitor is placed as close as possible to and connected to this pin and SW pin.

Ground pin.

This pin is the error amplifiers inverting input. This pin is connected via resistor divider to

the output of the switching regulator to set the output DC voltage.

This pin is the output of the error amplifier and together with FB pin is used to compensate

the voltage control feedback loop.

This pin is connected to source of high side FETs and provide return path for the high

side driver.

High side gate driver output.

Low side gate driver output.

Voltage supply for the internal 5V regulator, LDO controller and low side driver.

Oscillator's frequency can be set by using an external resistor from this pin to GND.

Pulling this pin down below 0.3V shuts down both controllers.

LDO controller feedback input. This pin is connected via resistor divider to the output of

the LDO to set the output DC voltage.

LDO controller output. This pin is controlling the gate of an external NCH MOSFET. The

maximum rating of this pin is 16V.

Connecting this pin to 5VREG voltage control mode will be chosen.

Connecting this pin to ground, constant on time control mode will be chosen.

Connecting this pin to 5VREG, synchronous mode will be chosen.

Connecting this pin to ground, diode emulation mode will be chosen, LDRV will be off

when inductor current becomes negative current.

Reference input voltage for error amplifier.

2.5V external reference. OCP trigger level is set by connect resistor from this pin to

ground.

PGOOD indicator for switching regulator. It requires a pull up resistor to Vcc or lower

voltage. When FB pin reaches 85% of the reference voltage PGOOD transitions from LO

to HI state.

VCC

BST

GND

FB

COMP

SW

HDRV

LDRV

VIN

RT

LDO_FB

LDO_DRV

MODE

FCCM

REFIN

VREF_OC

PGOOD