Block Diagram

2

Pin Configuration & Marking Information

Top View

SOT23 5

-

BL: Product Code

of PAM2309

V:

Output Voltage

Y:

Year

W: Week

X:

Internal Code

,

Power Analog Microelectronics Inc

www.poweranalog.com

PAM2309

1A Step-Down DC-DC Converter

Name

Function

VIN

Chip main power supply pin

GND

Ground

EN

Enable control input. Force this pin voltage above 1.5V, enables the chip, and below

0.3V shuts down the device.

VOUT/FB

VOUT: Output voltage feedback pin, an internal resistive divider divides the output

voltage down for comparison to the internal reference voltage.

FB: Feedback voltage to internal error amplifier, the threshold voltage is 0.5V.

SW

The drains of the internal main and synchronous power MOSFET.

NC

No connection

1

2

3

5

4

VIN

GND

EN

SW

VOUT/FB

Pin Description

12

11

10

9

13

14

15

16

1

2

3

4

8

7

6

5

VOUT/FB

GND

GND

GND

VIN

VIN

VIN

VIN

P2309V

XXXYW

DFN 2x2 6L

Top View

VOUT/FB

GND

SW

1

2

3

6

5

4

NC

EN

VIN

EN

R1

R2

VOUT/FB

PWM

COMP

+

-

IAMP

+

-

IRCMP

SW

GND

SYNCHRONOUS

RECTIFIER NCH

()

MAIN

SWITCH PCH

()

VIN

COMP

VIN

SHUTDOWN

OSC

RS LATCH

0.5VREF

FREQ

SHIFT

-

+

EA

SQ

RQ

SWITCHING

LOGIC

AND

BLANKING

CIRCUIT

SLOPE

COMP

1.5M

OSC

ANTI

SHOOT

THRU

-

-

QFN 3x3 16L

Top View

08/2009 Rev 1.1