November 2010
2008 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FAN5365 Rev. 1.0.4
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FAN5365
1A / 0.8A, 6MHz Digitally Programmable Regulator
Features
High Efficiency (>88%) at 6MHz
800mA or 1A Output Current
Regulation Maintained with VIN from 2.3V to 5.5V
6-Bit VOUT Programmable from 0.75 to 1.975V
6MHz Fixed-Frequency Operation (PWM Mode)
Excellent Load and Line Transient Response
Small Size, 470nH Inductor Solution
±2% DC Voltage Accuracy in PWM Mode
25ns Minimum On-Time
High-Efficiency, Low-Ripple, Light-Load PFM
Smooth Transition between PWM and PFM
40
μA Operating PFM Quiescent Current
I
2C-Compatible Interface up to 3.4Mbps
Pin-Selectable or I
2C Programmable Output Voltage
9-Bump, 1.27 x 1.29mm, 0.4mm Pitch WLCSP Package
Applications
3G, WiFi
, WiMAX, and WiBro Data Cards
Netbooks
, Ultra-Mobile PCs
SmartReflex-Compliant Power Supply
Split Supply DSPs and
μP Solutions OMAP, XSCALE
Handset Graphic Processors (NVIDIA
, ATI)
Description
The FAN5365 is a high-frequency, ultra-fast transient
response,
synchronous
step-down,
DC-DC
converter
optimized for low-power applications using small, low-cost
inductors and capacitors. The FAN5365 supports up to
800mA or 1A load current.
The FAN5365 is ideal for mobile phones and similar portable
applications powered by a single-cell Lithium-Ion battery.
With an output voltage range adjustable via I
2C interface
from 0.75V to 1.975V, it supports low-voltage DSPs and
processors, core power supplies, and memory modules in
smart phones, data cards, and hand-held computers.
The FAN5365 operates at 6MHz (nominal) fixed switching
frequency in PWM mode.
During light-load conditions, the regulator includes a PFM
mode to enhance light-load efficiency. The regulator
transitions smoothly between PWM and PFM modes with no
glitches on VOUT. In hardware shutdown, the current
consumption is reduced to less than 200nA.
The serial interface is compatible with fast / standard mode,
fast mode plus, and high-speed mode I
2C specifications,
allowing transfers up to 3.4Mbps. This interface is used for
dynamic voltage scaling with 12.5mV voltage steps, for
reprogramming the mode of operation (PFM or forced
PWM), or to disable/enable the output voltage.
The chip's advanced protection features include short-circuit
protection and current and temperature limits. During a
sustained over-current event, the IC shuts down and restarts
after a delay to reduce average power dissipation into a
fault.
During startup, the IC controls the output slew rate to
minimize input current and output overshoot at the end of
soft-start. The IC maintains a consistent soft-start ramp,
regardless of output load during startup.
The FAN5365 is available in a 1.27 x 1.29mm, 9-bump
WLCSP package.
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