POWER MANAGEMENT



SC633

Fixed 5.3V Output

Charge Pump Regulator

Features

Input voltage range — 2.9V to 5.5V

V

Continuous output current — 275mA, V

Peak output current — 400mA

Three charge pump modes — x, .5x and 2x

Output ripple ≤ 40mV

Short circuit, over-voltage, and over-temperature

protection

Soft-start functionality

Shutdown current — 0.µA, typical

Ultra thin package — 2 x 2 x 0.6 (mm)

Lead-free and halogen-free

WEEE and RoHS compliant

Applications

Mobile phones

MP3 players

USB On-The-Go

Multi-LED backlit LCDs

Compact flash/CF+ products

PMPs

Digital video cameras

Digital still cameras

PDAs

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Description

The SC633 is a high-current voltage regulator using

Semtech’s proprietary low-noise charge pump technol-

ogy. Performance is optimized for use in single Li-Ion

battery cell applications. The regulator provides the per-

formance of a linear, low drop-out (LDO) voltage regulator

when the input is greater than 5.3V. Unlike an LDO, drop-

out is avoided when the input is less than 5.3V. Instead, a

charge pump is activated to provide voltage boost and

the head-room needed for voltage regulation.

the full output current. The charge pump provides a low

EMI solution compared to inductive boost regulators.

The SC633’s charge pump has three modes of operation:

2x, .5x, and x modes. The 2x and .5x modes deliver

current to the load in each of two phases. The x mode

turns off the charge pump, delivering current through an

LDO. When active, the charge pump provides low-ripple

operation at 200kHz, which is typically less than 30mVpp

at the output. The SC633 is capable of delivering 275mA

output capacitor is used for decoupling the load and for

smoothing mode transitions. Hysteresis is provided to

prevent chatter between charge pump modes.

SC633

OUT

C1+

IN

GND

EN

C1-

C2+

C2-

22µF

22µF

2.2µF

2.2µF

Chip

enable

Typical Application Circuit

Rev 2.0

US Patent: 7,808,220