FAN5353 Datasheet, PDF (2/13 Pages) Fairchild Semiconductor – 3MHz, 3A Synchronous Buck Regulator

Table 1. Recommended External Components for 3A Maximum Load Current
Component
Description
Vendor
Parameter Typ.
Units
Vishay IHLP1616ABER47M01
L
0.47
μH
L1
470nH nominal
Coiltronics SD12-R47-R
TDK
VLC5020T-R47N
DCR
20
mΩ
MURATA LQH55PNR47NT0
COUT
CIN
CIN1
2 pieces
10μF, 6.3V, X5R, 0805
10μF, 6.3V, X5R, 0805
10nF, 25V, X7R, 0402
GRM21BR60J106M (Murata)
C2012X5R0J106M (TDK)
GRM155R71E103K (Murata)
C1005X7R1E103K (TDK)
C
10.0
μF
C
10
nF
CVCC
R3⁽¹⁾
4.7μF, 6.3V, X5R, 0603
Resistor: 1Ω 0402
GRM188R60J475K (Murata)
C1608X5R0J475K (TDK)
any
C
4.7
μF
R
1
Ω
Note:
1. R3 is optional and improves IC power supply noise rejection. See Layout recommendations for more information.
Pin Configuration
FB 1
VOUT 2
PGND 3
PGND 4
SW 5
SW 6
P1
(GND)
12 NC
11 PGOOD
10 EN
9 VCC
8 PVIN
7 PVIN
Figure 2. 12-Pin, 3x3.5mm MLP (Top View)
Pin Definitions
Pin # Name Description
1
FB
FB. Connect to resistor divider. The IC regulates this pin to 0.8V.
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.
© 2009 Fairchild Semiconductor Corporation
FAN5353 • Rev. 1.0.2
2
www.fairchildsemi.com