ISENSE

GND

PGND

VIN

PGATE

ADJ

FB

EN

1

2

3

4

5

6

7

8

LM3489

SNVS443A – MAY 2006 – REVISED JUNE 2008

www.ti.com

Connection Diagram

Figure 1. 8 Lead Plastic MSOP-8 Top View

Pin Functions

Pin Descriptions

Pin #

Name

Description

1

ISENSE

The current sense input pin. This pin should be connected to the PFET drain terminal directly

or through a series resistor up to 600 ohm for 28V>Vin>35V.

2

GND

Signal ground.

3

EN

Enable pin. Connect EN pin to ground to shutdown the part or float to enable operation

(Internally pulled high). This pin can also be used to perform UVLO function.

4

FB

The feedback input. Connect the FB to a resistor voltage divider between the output and

GND for an adjustable output voltage.

5

ADJ

Current limit threshold adjustment. Connected to an internal 5.5µA current source. A resistor

is connected between this pin and VIN. The voltage across this resistor is compared with the

ISENSE pin voltage to determine if an over-current condition has occurred.

6

PGND

Power ground.

7

PGATE

Gate Drive output for the external PFET. PGATE swings between VIN and VIN-5V.

8

VIN

Power supply input pin.

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

2

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