NCP1034

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3

PIN FUNCTION DESCRIPTION

PIN

PIN NAME

DESCRIPTION

1

Current limit set point. A resistor from this pin to GND will set the positive and negative current limit threshold

2

FB

Inverting input to the error amplifier. This pin is connected directly to the output of the regulator via resistor

divider to set the output voltage and provide feedback to the error amplifier.

3

COMP

Output of error amplifier. An external resistor and capacitor network is typically connected from this pin to ground

to provide loop compensation.

4

SS/SD

Soft−Start / Shutdown. This pin provides user programmable soft−start function. External capacitor connected

from this pin to ground sets the startup time of the output voltage. The converter can be shutdown by pulling this

pin below 0.3 V.

5

SYNC

The internal oscillator can be synchronized to an external clock via this pin and other IC’s can be synchronized

via this pin to internal oscillator. If it is not used this pin should be connected via 10 k

W resistor to ground.

6

Power Ground. This pin serves as a separate ground for the MOSFET driver and should be connected to the

system’s power ground plane.

7

LDRV

Output driver for low side MOSFET.

8

This pin provides biasing for the internal low side driver. A minimum of 0.1

mF, high frequency capacitor must be

connected from this pin to power ground.

9

VB

This pin powers the high side driver and must be connected to a voltage higher than input voltage. A minimum of

0.1

mF, high frequency capacitor must be connected from this pin to switch node.

10

HDRV

Output driver for high side MOSFET

11

Switch Node. This pin is connected to the source of the upper MOSFET and the drain of the lower MOSFET.

This pin is return path for the upper gate driver.

12

This pin provides power for the internal blocks of the IC. A minimum of 0.1

mF, high frequency capacitor must be

connected from this pin to ground.

13

Overcurrent sensing input. A serial resistor from this pin to drain of low MOSFET must be used to limit the

current into this pin.

14

GND

Signal ground for internal reference and control circuitry.

15

Connecting a resistor from this pin to ground sets the oscillator frequency.

16

UVLO

An external voltage divider is used to set the undervoltage threshold levels.