Datasheet LTC3402 (Analog Devices)

LTC3402 2A, 3MHz Micropower Synchronous Boost Converter
U FEATURES DESCRIPTIO
■
Synchronous Rectification: Up to 97% Efficiency
The LTC®3402 is a high efficiency, fixed frequency, step- ■
2A Switch Current Rating
up DC/DC converter that operates from an input voltage ■
Fixed Frequency Operation Up to 3MHz
below 1V. The device includes a 0.16Ω N-channel MOSFET ■
Wide Input Range: 0.5V to 5V
switch and a 0.18Ω P-channel synchronous rectifier. ■
Very Low Quiescent Current: 38
μ
A (Burst Mode®
Switching frequencies up to 3MHz are programmed with
Operation)
an external timing resistor and the oscillator can be ■ 2.6V to 5.5V Adjustable Output Voltage synchronized to an external clock. An external Schottky ■ 0.85V (Typ) Start-Up Voltage diode is optional but will slightly improve efficiency. ■ No External Schottky Diode Required (VOUT < 4.3V) Quiescent current is only 38μA in Burst Mode operation, ■ Synchronizable Switching Frequency maximizing battery life in portable applications. Burst ■ Burst Mode Enable Control Mode operation is user controlled and can be enabled by ■ Antiringing Control Reduces Switching Noise driving the MODE/SYNC pin high. If the MODE/SYNC pin ■ PGOOD Output has either a clock or is driven low, then fixed frequency ■ OPTI-LOOP® Compensation switching is enabled. ■ Very Low Shutdown Current: < 1μA ■ Small 10-Pin MSOP Package Other features include a 1μA shutdown, antiringing con-
U
trol, open-drain power good output, thermal shutdown
APPLICATIO S
and current limit. The LTC3402 is available in the 10-lead thermally enhanced MSOP package. Lower current appli- ■ Cellular Telephones cations should use the 1A rated LTC3401 synchronous ■ Handheld Computers boost converter. Applications that require VOUT < 2.6V ■ MP3 Players should use the LTC3424. ■ 2-Way Pagers , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ GPS Receivers Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. ■ Battery Backup Supplies ■ CCFL Backlights
U TYPICAL APPLICATIO All Ceramic Capacitor 2-Cell to 3.3V at 1A Step-Up Converter Efficiency
L1 100 2.2 Burst Mode μH V V IN = 1.8V to 3V OUT 90 OPERATION 3.3V 1A 80 1MHz LTC3402 3 4 70 CONSTANT V R2 IN SW FREQUENCY 909k 60 10 7 SHDN VOUT 50 + 2 2 8 C2 CELLS MODE/SYNC FB 40 44μF EFFICIENCY (%) (2 × 22μF) 6 9 30 PGOOD VC C3 R1 20 C1 1 5 10μF R 470pF 549k t GND 10 VIN = 2.4V WITH SCHOTTKY R R5 C4 t 0 30.1k 82k 4.7pF 0.1 1 10 100 1000 IOUT (mA) 3402 TA02 C1: TAIYO YUDEN JMK212BJ106MG 3402 TA01 0 = FIXED FREQ C2: TAIYO YUDEN JMK325BJ226MM 1 = Burst Mode OPERATION L1: COILCRAFT: D03316P-222 3402fb 1