October 2007
FAN5631 / FAN5632
Regulated Step-Down Charge Pump DC/DC Converter
Features
90% Peak Efficiency
Low EMI
Low Ripple
Selectable Output Voltage:1.2V/1.5V for FAN5631
Efficiency Optimizer Feature for FAN5632
Input Voltage Range: 2.2V to 5.5V
Output Current: Up to 250mA
±5% Output Voltage Accuracy
30µA Operating Current
ICC<1mA in Shutdown Mode
1.5MHz Operating Frequency
Shutdown Isolates Output from Input
Soft-Start Limits Inrush Current
Short-Circuit and Over-Temperature Protection
Minimum External Component Count
10-Lead 3x3mm MLP Package
Applications
Cell Phones
Handheld Computers
Portable Electronic Equipment
Core Supply to Next-Generation Processors
Low-Voltage DC Bus
Digital Cameras
DSP Supplies
Description
The FAN5631/FAN5632 is an advanced, third-
generation switched capacitor step-down DC/DC
converter utilizing Fairchild's proprietary ScalarPump
technology. This innovative architecture utilizes scalar
switch re-configuration and fractional switching
techniques to produce low output ripple, lower ESR
spikes, and improve efficiency over a wide load range.
The FAN5631/FAN5632 produces a fixed regulated
output voltage from an input voltage of 2.2V to 5V.
To maximize efficiency, the FAN5631/5632 achieves
regulation by skipping pulses. Depending on load
current, the size of the switches are scaled dynamically;
consequently, current spikes and EMI are minimized.
An internal soft-start circuitry prevents excessive current
from the supply. The device is internally protected
against short-circuit and over-temperature conditions.
The FAN5631 has a dual-output voltage feature. When
VSEL is high, VOUT is 1.5V; and when VSEL is low, VOUT is
1.2V.
The FAN5632 has an efficiency optimizer feature that,
when enabled, changes the switch mode configuration
from 2:1 to 1:1 at the lower threshold of VIN. The
efficiency is maintained at its peak level over a wider
range of input voltages. In addition, VOUT varies from
1.2V to 1.5V as a result of this efficiency optimization. If
the efficiency optimizer is not enabled, VOUT is regulated
to 1.5V.
Both the FAN5631 and FAN5632 are available in a 10-
lead 3x3mm MLP package.
Ordering Information
Part Number
Package
FAN5631MPX
10-Lead 3x3mm Molded Leadless Package (MLP)
FAN5632MPX
10-Lead 3x3mm Molded Leadless Package (MLP)
All packages are lead free per JEDEC: J-STD-020B standard.
© 2006 Fairchild Semiconductor Corporation
FAN5631/FAN5632 Rev. 1.0.2
Packing Method
Tape and Reel
Tape and Reel
www.fairchildsemi.com