8

7

6

5

4

3

2

1

Exposed Pad on Bottom

Connect to Ground

FB

GND

ADJ

PGATE

ISEN

VCC

RT

VIN

1

2

3

4

5

8

7

6

Exposed Pad on Bottom

Connect to Ground

FB

PGATE

ISEN

GND

VCC

ADJ

RT

VIN

1

2

3

4

5

8

7

6

FB

PGATE

ISEN

GND

VCC

ADJ

RT

VIN

LM5085, LM5085-Q1

www.ti.com

SNVS565I – NOVEMBER 2008 – REVISED AUGUST 2015

5 Pin Configuration and Functions

8-Pins

8-Pins

8-Pins

HVSSOP Package

WSON Package

VSSOP Package

Top View

Top View

Top View

Pin Functions

PIN

I/O

DESCRIPTION

APPLICATION INFORMATION

NAME

NO.

ADJ

1

I

Current Limit Adjust

The current limit threshold is set by an external resistor from VIN to ADJ

RT

2

I

On-Time Control and Shutdown

An external resistor from VIN to RT sets the buck switch on-time and

switching frequency. Grounding this pin shuts down the controller.

FB

3

I

Voltage Feedback From the

Input to the regulation and over-voltage comparators. The regulation

Regulated Output

level is 1.25V.

GND

4

-

Circuit Ground

Ground reference for all internal circuitry

ISEN

5

I

Current Sense Input for Current limit

Detection.

to the PFET source and the sense resistor when using a current sense

resistor.

PGATE

6

O

Gate Driver Output

Connect to the gate of the external PFET.

VCC

7

O

Output of the gate driver bias

Output of the negative voltage regulator (relative to VIN) that biases the

regulator

PFET gate driver. A low ESR capacitor is required from VIN to VCC,

located as close as possible to the pins.

VIN

8

I

Input Supply Voltage

The operating input range is from 4.5V to 75V. A low ESR bypass

capacitor must be located as close as possible to the VIN and GND pins.

EP

-

Exposed Pad

Exposed pad on the underside of the package (HVSSOP and WSON

only). This pad is to be soldered to the PC board ground plane to aid in

heat dissipation.

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)

(1) (2)

MIN

MAX

UNIT

VIN to GND

–0.3

76

V

ISEN to GND

–3

V

ADJ to GND

–0.3

V

RT, FB to GND

–0.3

7

V

VIN to VCC, VIN to PGATE

–0.3

10

V

–65

150

°C

(1)

Absolute Maximum Ratings are limits beyond which damage to the device may occur. Recommended Operating Conditions are

conditions under which operation of the device is intended to be functional. For specifications and test conditions, see the Electrical

Characteristics .

(2)

If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and

specifications.

Copyright © 2008–2015, Texas Instruments Incorporated

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