Datasheet LTC3422 (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | 1.5A, 3MHz Synchronous Step-Up DC/DC Converter with Output Disconnect |
| Páginas / Página | 16 / 1 — FEATURES. DESCRIPTIO. 700mA Continuous/1A Pulsed Output Current. for … |
| Formato / tamaño de archivo | PDF / 271 Kb |
| Idioma del documento | Inglés |
FEATURES. DESCRIPTIO. 700mA Continuous/1A Pulsed Output Current. for Li-Ion to 5V Applications
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LTC3422 1.5A, 3MHz Synchronous Step-Up DC/DC Converter with Output Disconnect
U FEATURES DESCRIPTIO
■
700mA Continuous/1A Pulsed Output Current
The LTC®3422 is a high efficiency, current mode, fixed
for Li-Ion to 5V Applications
frequency, step-up DC/DC converter with true output ■
Synchronous Rectification: Up to 96% Efficiency
disconnect and inrush current limiting. The part is guaran- ■
True Output Disconnect
teed to start up from an input voltage of 1V. The device ■
Inrush Current Limiting
includes a 0.20Ω N-channel MOSFET switch and a 0.24Ω ■
Adjustable Automatic Burst Mode® Operation
P-channel MOSFET synchronous rectifier. The output ■ Low Noise, Fixed Frequency Operation from voltage, switching frequency, soft-start time, Burst Mode 100kHz to 3MHz threshold and loop compensation are all simply pro- ■ 0.5V to 4.5V Input Range grammed using tiny external passive components. ■ 2.25V to 5.25V Adjustable Output Voltage Quiescent current is only 25µA during Burst Mode opera- ■ Guaranteed 1V Start-Up tion, maximizing battery life in portable applications. The ■ Programmable Soft-Start oscillator frequency can be programmed up to 3MHz and ■ Synchronizable Oscillator can be synchronized to an external clock applied to the ■ Low Quiescent Current: 25µA SYNC pin. ■ < 1µA Shutdown Current ■ Anti-Ringing Control Other features include 1µA shutdown, short-circuit protec- ■ Small (3mm × 3mm × 0.75mm) Thermally Enhanced tion, anti-ringing control, thermal shutdown and current 10-Pin DFN Package limit. The LTC3422 is available in a (3mm × 3mm × 0.75mm)
U
10-pin DFN package.
APPLICATIO S
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. ■ Wireless Handsets All other trademarks are the property of their respective owners. ■ Handheld Computers ■ GPS Receivers ■ MP3 Players
U TYPICAL APPLICATIO 2.4V to 3.3V Efficiency and Power Loss
100 10000 4.7µH BURST V 90 IN EFFICIENCY 1.8V TO 3.2V + 80 1000 4.7 2 CELLS µF V POWER LOSS (mW) IN SW 70 PWM VOUT EFFICIENCY SYNC V 3.3V OUT 60 100 22µF 600mA 931k LTC3422 50 OFF ON SHDN FB 40 10 PWM EFFICIENCY (%) POWER V 549k 30 C BURST LOSSES 1nF SS RT GND 20 BURST 1 POWER 10 15k 22pF 0.1µF 28k 2.2nF 301k LOSSES fOSC = 1MHz 0 0 0.1 1 10 100 1000 3422 TA01a LOAD CURRENT (mA) 3422 TA01b 3422fa 1
U FEATURES DESCRIPTIO
■
700mA Continuous/1A Pulsed Output Current
The LTC®3422 is a high efficiency, current mode, fixed
for Li-Ion to 5V Applications
frequency, step-up DC/DC converter with true output ■
Synchronous Rectification: Up to 96% Efficiency
disconnect and inrush current limiting. The part is guaran- ■
True Output Disconnect
teed to start up from an input voltage of 1V. The device ■
Inrush Current Limiting
includes a 0.20Ω N-channel MOSFET switch and a 0.24Ω ■
Adjustable Automatic Burst Mode® Operation
P-channel MOSFET synchronous rectifier. The output ■ Low Noise, Fixed Frequency Operation from voltage, switching frequency, soft-start time, Burst Mode 100kHz to 3MHz threshold and loop compensation are all simply pro- ■ 0.5V to 4.5V Input Range grammed using tiny external passive components. ■ 2.25V to 5.25V Adjustable Output Voltage Quiescent current is only 25µA during Burst Mode opera- ■ Guaranteed 1V Start-Up tion, maximizing battery life in portable applications. The ■ Programmable Soft-Start oscillator frequency can be programmed up to 3MHz and ■ Synchronizable Oscillator can be synchronized to an external clock applied to the ■ Low Quiescent Current: 25µA SYNC pin. ■ < 1µA Shutdown Current ■ Anti-Ringing Control Other features include 1µA shutdown, short-circuit protec- ■ Small (3mm × 3mm × 0.75mm) Thermally Enhanced tion, anti-ringing control, thermal shutdown and current 10-Pin DFN Package limit. The LTC3422 is available in a (3mm × 3mm × 0.75mm)
U
10-pin DFN package.
APPLICATIO S
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. ■ Wireless Handsets All other trademarks are the property of their respective owners. ■ Handheld Computers ■ GPS Receivers ■ MP3 Players
U TYPICAL APPLICATIO 2.4V to 3.3V Efficiency and Power Loss
100 10000 4.7µH BURST V 90 IN EFFICIENCY 1.8V TO 3.2V + 80 1000 4.7 2 CELLS µF V POWER LOSS (mW) IN SW 70 PWM VOUT EFFICIENCY SYNC V 3.3V OUT 60 100 22µF 600mA 931k LTC3422 50 OFF ON SHDN FB 40 10 PWM EFFICIENCY (%) POWER V 549k 30 C BURST LOSSES 1nF SS RT GND 20 BURST 1 POWER 10 15k 22pF 0.1µF 28k 2.2nF 301k LOSSES fOSC = 1MHz 0 0 0.1 1 10 100 1000 3422 TA01a LOAD CURRENT (mA) 3422 TA01b 3422fa 1