LM5035A

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SNVS537F – JANUARY 2008 – REVISED APRIL 2013

Pin Descriptions for LM5035A and LM5035A–1 (continued)

HTSSOP 20

WQFN PIN

HTSSOP 28

Name

Description

Application Information

PIN LM5035A

LM5035A

PIN LM5035A-1

11

11

15

HB

Boost voltage for the HO

An external diode is required from VCC

driver

to HB and an external capacitor is

required from HS to HB to power the HO

gate driver.

12

12

16

HS

Switch node

Connection common to the transformer

and both power switches. Provides a

return path for the HO gate driver.

13

13

17

HO

High side gate drive output.

Output of the high side PWM gate

driver. Capable of sinking 2A peak

current

14

14

19

LO

Low side gate dfrive output. Output of the low side PWM gate driver.

Capable of sinking 2A peak current.

15

15

20

PGND

Power Ground

Connect directly to Analog Ground.

16

16

21

VCC

Output of the high voltage

If an auxiliary winding raises the voltage

start-up regulator.The VCC

on this pin above the regulation setpoint,

voltage is regulated to

the Start-up Regulator will shutdown,

7.6V.

thus reducing the internal power

dissipation.

17

17

22

SR2

Synchronous rectifier driver

Control output of the synchronous FET

output.

gate. Capable of 0.5A peak current.

18

18

23

SR1

Synchronous rectifier driver

Control output of the synchronous FET

output.

gate. Capable of 0.5A peak current.

19

19

24

REF

Output of 5V Reference

Maximum output current is 20mA.

Locally decoupled with a 0.1µF

capacitor.

20

21

28

VIN

Input voltage source

Input to the Start-up Regulator.

Operating input range is 13V to 100V

with transient capability to 105V. For

power sources outside of this range, the

LM5035A can be biased directly at VCC

by an external regulator.

1

NC

2

NC

3

NC

4

NC

18

NC

25

NC

26

NC

27

NC

EP

EP

EP

Exposed Pad, underside of

No electrical contact. Connect to system

package

ground plane for reduced thermal

resistance.

1

NC

No connection

No electrical contact.

10

NC

No connection

No electrical contact.

20

NC

No connection

No electrical contact.

22

NC

No connection

No electrical contact.

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.

Copyright © 2008–2013, Texas Instruments Incorporated

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