© 2009 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FAN5353 • Rev. 1.0.3

2

Table 1. Recommended External Components for 3 A Maximum Load Current

Component

Description

Vendor

Parameter

Typ.

Units

L1

470 nH nominal

Vishay — IHLP1616ABER47M01

Coiltronics — SD12-R47-R

TDK — VLC5020T-R47N,

MURATA — LQH55PNR47NT0

L

0.47

µH

DCR

20

m

Ω

2 pieces

10

µF, 6.3 V, X5R, 0805

GRM21BR60J106M (Murata)

C2012X5R0J106M (TDK)

C

10.0

µF

10

µF, 6.3 V, X5R, 0805

10 nF, 25 V, X7R, 0402

GRM155R71E103K (Murata)

C1005X7R1E103K (TDK)

C

10

nF

4.7

µF, 6.3 V, X5R, 0603

GRM188R60J475K (Murata)

C1608X5R0J475K (TDK)

C

4.7

µF

R3

(1)

Resistor: 1

Ω 0402

any

R

1

Ω

Note:

1.

R3 is optional and improves IC power supply noise rejection. See Layout recommendations for more information.

Pin Configuration

Figure 2. 12-Pin, 3 x 3.5 mm MLP (Top View)

Pin Definitions

Pin #

Name

Description

1

FB

FB. Connect to resistor divider. The IC regulates this pin to 0.8 V.

2

VOUT

VOUT. Sense pin for VOUT. Connect to COUT.

3, 4

PGND

Power Ground. Low-side MOSFET is referenced to this pin. CIN and COUT should be returned with a

minimal path to these pins.

5, 6

SW

Switching Node. Connect to inductor.

P1

GND

Ground. All signals are referenced to this pin.

7, 8

PVIN

Power Input Voltage. Connect to input power source. Connect to CIN with minimal path.

9

VCC

IC Bias Supply. Connect to input power source. Use a separate bypass capacitor CVCC from this pin

to the P1 GND terminal between pins 1 and 12.

10

EN

Enable. The device is in shutdown mode when this pin is LOW. Do not leave this pin floating.

11

PGOOD

Power Good. This open-drain pin pulls LOW if the output falls out of regulation or is in soft-start.

12

NC

This pin has no function and should be tied to GND.

Note:

2.

P1 is the bottom heat-sink pad. Ground plane should flow through pins 3, 4, 12, and P1 and can be extended through pin

11 if PGOOD’s function is not required to improve IC cooling.

FB

VOUT

PGND

PGND

SW

SW

NC

PGOOD

EN

VCC

PVIN

PVIN

6

5

4

3

2

1

7

8

9

10

11

12

P1

(GND)