1.2MHZ MICROPOWER SYNCHRONOUS STEP-UP CONVERTER
FSP3603
FEATURES
High Efficiency: Up to 92%
1.2MHz Constant Switching Frequency
3.3V Output Voltage at I
OUT
=100mA from a
Single AA Cell; 3.3V Output Voltage at
I
OUT
=400mA from two AA cells
Low Start-up Voltage: 0.85V
Integrated main switch and synchronous rectifier. No
Schottky Diode Required
2.5V to 5V Output Voltage Range
Automatic Pulse Skipping Mode Operation
Tiny External Components
<1 µA Shutdown Current
Antiringing Control Reduces EMI
Space Saving 6-Pin Thin SOT23 Package
GENERAL DESCRIPTION
The FSP3603 is a 1.2MHz constant frequency, current
mode PWM step-up converter. It can supply 3.3V
output voltage at 100mA from a single AA Cell. The
device integrates a main switch and a synchronous
rectifier for high efficiency without an external Schottky
diode. A switching frequency of 1.2MHz allows the use
of tiny, low profile inductors and ceramic capacitors.
The current mode PWM operation with internal
compensation provides excellent line and load
transient characteristics. The FSP3603 features Pulse
Skipping Mode operation at light loads to avoid
unacceptable ripple voltage.
The FSP3603 is offered in a low profile (1mm) small
6-Pin SOT23 Package
APPLICATIONS
Cellular and Smart Phones
Microprocessors and DSP Core Supplies
Wireless and DSL Modems
MP3 Player
Digital Still and Video Cameras
Portable Instruments
PIN CONFIGURATION
(Top View)
VIN
VOUT SHDN
6
5
4
1
SW
2
GND
3
FB
Pin Number
1
2
3
4
5
6
Pin Name
SW
GND
FB
SHDN
VOUT
VIN
Pin Function
Power Switch Pin. It is the switch node connection to Inductor.
Ground Pin
Feedback Input Pin. Connect FB to the center point of the external resistor
divider. The feedback threshold voltage is 1.23V.
Chip Shutdown Signal Input. Logic high is normal operation mode, Logic
Low is Shutdown. Typically, this pin is connected to V
IN
through a 1 MΩ
resistor.
Power Output Pin. V
OUT
is held 0.6V below than V
IN
in shutdown.
Power Supply Input. Must be closely decoupled to GND, Pin 2, with a 4.7µF
or greater ceramic capacitor.
1/9
2007-4-19
FOSLINK [ FOSLINK SEMICONDUCTOR CO.,LTD ]
