AAT2158

1.5A Low Noise Step-Down Converter

2

2158.2007.10.1.1

Pin Descriptions

Pin Configuration

QFN33-16

(Top View)

VP

VP

VP

PGND

PGND

PGND

1

2

3

4

12

11

10

9

VCC

FB

Pin #

Symbol

Function

1, 2, 3

PGND

Main power ground return pin. Connect to the output and input capacitor return. (See

board layout rules.)

4

FB

Feedback input pin. For an adjustable output, connect an external resistive divider to

this pin. For fixed output voltage versions, FB is the output pin of the converter.

5

SGND

Signal ground. Connect the return of all small signal components to this pin. (See

board layout rules.)

7

EN

Enable input pin. A logic high enables the converter; a logic low forces the AAT1158

into shutdown mode reducing the supply current to less than 1µA. The pin should not

be left floating.

6, 8, 16

N/C

Not internally connected.

9

VCC

Bias supply. Supplies power for the internal circuitry. Connect to input power.

10, 11, 12

VP

Input supply voltage for the converter power stage. Must be closely decoupled to

PGND.

13, 14, 15

LX

Connect inductor to these pins. Switching node internally connected to the drain of

both high- and low-side MOSFETs.

EP

Exposed paddle (bottom); connect to PGND directly beneath package.