1

SW

8

VIN

2

BST

7

VCC

3

RCL

6

RT/SD

4

RTN

5

FB

Not to scale

1

SW

8

VIN

2

BST

7

VCC

3

RCL

6

RT/SD

4

RTN

5

FB

Not to scale

EP

3

LM5008A

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SNVS583H – MARCH 2009 – REVISED OCTOBER 2018

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5 Pin Configuration and Functions

DGK Package

8-Pin VSSOP

Top View

NGU Package

8-Pin WSON

Top View

Pin Functions

PIN

TYPE

DESCRIPTION

NO.

NAME

1

SW

P

Switching node: power switching node. Connect to the output inductor, re-circulating diode, and bootstrap

capacitor.

2

BST

I

Boost pin (bootstrap capacitor input): an external capacitor is required between the BST and the SW pins. A

0.01-µF ceramic capacitor is recommended. An internal diode charges the capacitor from VCC during each

off-time.

3

RCL

I

Current limit off-time set pin: a resistor between this pin and RTN sets the off-time when current limit is

detected. The off-time is preset to 35 µs if FB = 0 V.

4

RTN

G

Ground pin: ground for the entire circuit.

5

FB

I

Feedback input from regulated output: this pin is connected to the inverting input of the internal regulation

comparator. The regulation threshold is 2.5 V.

6

RT/SD

I

On-time set pin: a resistor between this pin and VIN sets the switch on time as a function of VIN. The

minimum recommended on time is 400 ns at the maximum input voltage. This pin can be used for remote

shutdown.

7

VCC

P

Output from the internal high voltage series pass regulator: this regulated voltage provides gate drive power

for the internal buck switch. An internal diode is provided between this pin and the BST pin. A local 0.47-µF

decoupling capacitor is required. The series pass regulator is current limited to 9 mA.

8

VIN

P

Input voltage: input operating range from 6 V to 95 V.

—

EP

G

Exposed pad: the exposed pad has no electrical contact. Connect to system ground plane for reduced

thermal resistance. (WSON package only)