1

2

3

4

5

6

7

8

SW

BST

RCL

FB

RTN

RON/SD

VCC

VIN

LM5009

SNVS402G – FEBRUARY 2006 – REVISED FEBRUARY 2013

www.ti.com

Connection Diagram

Figure 2. 8-Lead VSSOP or WSON

Pin Functions

Table 1. Pin Descriptions

Pin

Name

Description

Application Information

1

SW

Switching output

Power switching output. Connect to the inductor, re-circulating diode, and bootstrap

capacitor.

2

BST

Boost Pin

An external capacitor is required between the BST and the SW pins. A 0.022 µF

ceramic capacitor is recommended. An internal diode charges the capacitor from

3

RCL

Current Limit off-time set

A resistor between this pin and RTN sets the off-time when current limit is detected.

pin

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

4

RTN

Ground pin

Ground for the entire circuit.

5

FB

Feedback input from

This pin is connected to the inverting input of the internal regulation comparator. The

Regulated Output

regulation threshold is 2.5V.

6

RON/SD

On-time set pin

minimum recommended on-time is 250ns at the maximum input voltage. This pin

can be used for remote shutdown.

7

VCC

Output from the internal

If an auxiliary voltage is available to raise the voltage on this pin above the

high voltage startup

regulation set point (7V), the internal series pass regulator will shutdown, reducing

regulator. Regulated at

the IC power dissipation. Do not exceed 14V. This voltage provides gate drive

7.0V.

power for the internal Buck switch. An internal diode is provided between this pin

and the BST pin. A local 0.1µF decoupling capacitor is required.

8

VIN

Input voltage

Recommended operating range: 9.5V to 95V.

EP

Exposed pad

Exposed metal pad on the underside of the device. It is recommended to connect

(WSON package only)

this to the PC board ground plane to aid in heat dissipation.

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.

Absolute Maximum Ratings

(1)

-0.3V to 100V

BST to RTN

-0.3V to 114V

SW to RTN (Steady State)

-1V

2kV

BST to VCC

100V

BST to SW

14V

VCC to RTN

14V

All Other Inputs to RTN

-0.3 to 7V

Storage Temperature Range

-65°C to +150°C

(1)

Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which

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

(2)

The human body model is a 100pF capacitor discharged through a 1.5k

Ω resistor into each pin.

2

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