Datasheet LTC3401 (Analog Devices)

LTC3401 1A, 3MHz Micropower Synchronous Boost Converter
U FEATURES DESCRIPTIO
■
Synchronous Rectification: Up to 97% Efficiency
The LTC®3401 is a high efficiency, fixed frequency, step- ■
1A 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 5.5V (Operating)
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 1μA shutdown, antiringing control,
U
open-drain power good output, thermal shutdown and
APPLICATIO S
current limit. The LTC3401 is available in the 10-lead thermally enhanced MSOP package. Higher current appli- ■ Pagers cations should use the 2A rated LTC3402 synchronous ■ Handheld Instruments boost converter. Applications that require V ■ OUT < 2.6V Cordless Phones should use the LTC3423. ■ Wireless Handsets , 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 ■ CCFL Backlights
U TYPICAL APPLICATION All-Ceramic-Capacitor 2-Cell to 3.3V at 500mA Step-Up Converter
L1 4.7μH V V IN = 1.8V to 3V OUT
Efficiency
3.3V 100 500mA Burst Mode LTC3401 90 OPERATION 3 4 V R2 IN SW 909k 80 1MHz 10 7 SHDN VOUT 70 FIXED + FREQUENCY 2 2 8 60 CELLS MODE/SYNC FB C2 22μF 50 6 9 PGOOD VC C3 40 C1 EFFICIENCY (%) 1 5 470pF 4.7μF R1 R GND C4 30 t 4.7pF 549k 20 R R5 t 30.1k 82k 10 VIN = 2.4V WITH SCHOTTKY 0 0.1 1 10 100 1000 3404 TA01 0 = FIXED FREQUENCY C1: TAIYO YUDEN JMK212BJ475MG IOUT (mA) 1 = Burst Mode OPERATION C2: TAIYO YUDEN JMK325BJ226MM 3401 TA02 L1: SUMIDA CD43-4R7M 3401fb 1