FB

VIN

SW

RTN

BST

SM74301

8

6

5

3

4

1

2

7

SHUTDOWN

VCC

RCL

12V - 95V

Input

324k

C1

1.0 PF

332k

1.0k

3.01k

R3

3.0

GND

C2

22 PF

10.0V

L1

220 PH

C3

0.47 PF

C4

0.01 PF

D1

C5

0.1 PF

SM74301

SNVS719A – JULY 2011

www.ti.com

If the internal dissipation of the SM74301 produces excessive junction temperatures during normal operation,

good use of the pc board’s ground plane can help considerably to dissipate heat. The exposed pad on the

bottom of the WSON-8 package can be soldered to a ground plane on the PC board, and that plane should

extend out from beneath the IC to help dissipate the heat. Additionally, the use of wide PC board traces, where

possible, can also help conduct heat away from the IC. Judicious positioning of the PC board within the end

product, along with use of any available air flow (forced or natural convection) can help reduce the junction

temperatures.

Figure 12. SM74301 Example Circuit

Table 1. Bill of Materials

Item

Description

Part Number

Value

C1

Ceramic Capacitor

TDK C4532X7R2A105M

1 µF, 100V

C2

Ceramic Capacitor

TDK C4532X7R1E226M

22 µF, 25V

C3

Ceramic Capacitor

Kemet C1206C474K5RAC

0.47 µF, 50V

C4

Ceramic Capacitor

Kemet C1206C103K5RAC

0.01 µF, 50V

C5

Ceramic Capacitor

TDK C3216X7R2A104M

0.1 µF, 100V

D1

Schottky Power Diode

Diodes Inc. DFLS1100

100V, 1A

L1

Power Inductor

COILTRONICS DR125-221-R, or

220 µH

TDK SLF10145T-221MR65

Resistor

Vishay CRCW12063011F

3.01 k

Ω

Resistor

Vishay CRCW12061001F

1.0 k

Ω

R3

Resistor

Vishay CRCW12063R00F

3.0

Ω

Resistor

Vishay CRCW12063243F

324 k

Ω

Resistor

Vishay CRCW12063323F

332 k

Ω

U1

Switching Regulator

TI SM74301

12

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