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AMS4154

PIN DESCRIPTION

AMS4154

PIN

NUMBERS

NAME

DESCRIPTION

1

BST

Bootstrap. A capacitor is needed to drive the power switch’s drive above the supply

voltage. It is connected between LX and BST pins to form a floating supply across the

power switch driver.

2

VIN

Supply Voltage. The AMS4154 operates from a+5.5V to +32V unregulated input. C1 is

needed to prevent large voltage spikes from appearing at the input.

3

LX

Switch. This connects the inductor to VIN through the internal power switch.

4

GND

Ground. This pin is the ground for voltage reference and for the regulated output voltage.

For this reason care must be taken in its layout.

5

FB

Feedback. An external resistor divider from the output to GND, tapped to the FB pin sets

the output voltage.

6

COMP

Compensation. This node is the output of the transconductance error amplifier and the

input to the current comparator. Frequency compensation is done at this node by

connecting a series R-C to ground.

7

EN

Enable. A voltage greater than 2.5V enables operation. For complete low current shutdown

the EN pin voltage needs to be less than 2.3V.

8

REF

5V reference voltage capable of supplying 1mA for other external circuits.