FAN53541 Datasheet, PDF (1/15 Pages) Fairchild Semiconductor – 2.4 MHz, 5 A TinyBuck Synchronous Buck Regulator

February 2014
FAN53541
2.4 MHz, 5 A TinyBuck™ Synchronous Buck Regulator
Features
 2.4 MHz Fixed-Frequency Operation
 Best-in-Class Load Transient Response
 5 A Output Current Capability
 2.7 V to 5.5 V Input Voltage Range
 Adjustable Output Voltage: 0.8 V to 90% of V_IN
 PFM Mode for High Efficiency in Light Load
(Forced PWM Available on MODE Pin)
 50 µA Typical Quiescent Current in PFM Mode
 External Frequency Synchronization
 Low Ripple Light-Load PFM Mode with Forced
PWM Control
 Power Good Output
 Internal Soft-Start
 Input Under-Voltage Lockout (UVLO)
 Thermal Shutdown and Overload Protection
 No External Compensation Required
 20-Bump WLCSP
Applications
 Set-Top Box
 Hard Disk Drive
 Communications Cards
 DSP Power
Description
The FAN53541 is a step-down switching voltage regulator
that delivers an adjustable output from an input voltage
supply of 2.7 V to 5.5 V. Using a proprietary architecture with
synchronous rectification, the FAN53541 is capable of
delivering 5 A at over 90% efficiency, while maintaining a
very high efficiency of over 80% at load currents as low as
2 mA. The regulator operates at a nominal fixed frequency of
2.4 MHz, which reduces the value of the external
components to 470 nH for the output inductor and 20 µF for
the output capacitor. Additional output capacitance can be
added to improve regulation during load transients without
affecting stability and inductance up to 1.2 µH may be used
with additional output capacitance.
At moderate and light loads, pulse frequency modulation
(PFM) is used to operate the device in power-save mode
with a typical quiescent current of 50 µA. Even with such a
low quiescent current, the part exhibits excellent transient
response during large load swings. At higher loads, the
system automatically switches to fixed-frequency control,
operating at 2.4 MHz. In shutdown mode, the supply current
drops below 1 µA, reducing power consumption. PFM mode
can be disabled if constant frequency is desired. The
FAN53541 is available in a 20-bump 1.96 mm x 1.56 mm
Wafer-Level Chip-Scale Package (WLCSP).
C_IN
10µF
VIN
C_IN1
10nF
FAN53541
EN
MODE
PGOOD
SW ^L1
0.47H
GND
C_OUT
10µF
VOUT
FB
R1
C_OUT
10µF
Figure 1. Typical Application
Ordering Information
Part Number
FAN53541UCX
Temperature Range
Package
-40 to 85°C
20-Ball Wafer-Level, Chip-Scale Package (WLCSP),
4x5 Array, 0.4 mm Pitch, 250 µm Ball
Packing Method
Tape and Reel
© 2013 Fairchild Semiconductor Corporation
FAN53541 • Rev. 1.0.2
www.fairchildsemi.com