Datasheet LTC3542 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 500mA, 2.25MHz Synchronous Step-Down DC/DC Converter |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTION. High Effi ciency: Up to 96%. High Peak Switch … |
| File Format / Size | PDF / 222 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. High Effi ciency: Up to 96%. High Peak Switch Current: 1000mA. Low Output Ripple (<20mVP-P Typical)
Model Line for this Datasheet
Text Version of Document
LTC3542 500mA, 2.25MHz Synchronous Step-Down DC/DC Converter
FEATURES DESCRIPTION
■
High Effi ciency: Up to 96%
The LTC®3542 is a high effi ciency monolithic synchronous ■
High Peak Switch Current: 1000mA
buck converter using a constant frequency, current mode ■
Low Output Ripple (<20mVP-P Typical)
architecture. Supply current during operation is only
Burst Mode Operation: Only 26μA
26μA, dropping to <1μA in shutdown. The 2.5V to 5.5V ■
Very Low Quiescent Current: Only 26μA
input voltage range makes the LTC3542 ideally suited for ■
2.5V to 5.5V Input Voltage Range
single Li-Ion battery-powered applications. 100% duty ■
2.25MHz Constant Frequency Operation
cycle provides low dropout operation, extending battery ■
1MHz to 3MHz External Frequency Synchronization
life in portable systems. The output voltage is adjustable ■
Low Dropout Operation: 100% Duty Cycle
from 0.6V to VIN. Internal power switches are optimized ■
No Schottky Diode Required
to provide high effi ciency and eliminate the need for an ■ Internal Soft-Start Limits Inrush Current external Schottky diode. ■ 0.6V Reference Allows Low Output Voltages Switching frequency is internally set at 2.25MHz, allowing ■ Shutdown Mode Draws <1μA Supply Current the use of small surface mount inductors and capacitors, ■ ±2% Output Voltage Accuracy and it can synchronize to an external clock signal with a ■ Current Mode Operation for Excellent Line and Load frequency range of 1MHz to 3MHz through the MODE/ Transient Response SYNC pin. The LTC3542 is specifi cally designed to work ■ Overtemperature Protected well with ceramic output capacitors, achieving very low ■ Available in 6-Lead 2mm × 2mm DFN and Small TSOT output voltage ripple and a small PCB footprint. The LTC3542 can be confi gured for the power saving Burst
APPLICATIONS
Mode® Operation. For reduced noise and RF interference, ■ Cellular Telephones the MODE/SYNC pin can be confi gured for pulse skipping ■ Wireless and DSL Modems operation. ■ Digital Cameras ■ MP3 Players , LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■ PDAs and Other Handheld Devices Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885.
Effi ciency and Power Loss vs Output Current TYPICAL APPLICATION
100 1000 VIN = 3.6V 90 VOUT = 1.8V 2.2μH V 80 V OUT IN V 100 IN SW 1.8V 2.7V TO 5.5V POWER LOSS (mW) C 22pF IN 500mA 70 10μF LTC3542 60 CER 150k 50 10 RUN VFB COUT 40 MODE/SYNC 75k 10μF EFFICIENCY (%) CER 30 GND 3542 TA01a 1 20 10 0 0.1 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3542 TA01b 3542fa 1
FEATURES DESCRIPTION
■
High Effi ciency: Up to 96%
The LTC®3542 is a high effi ciency monolithic synchronous ■
High Peak Switch Current: 1000mA
buck converter using a constant frequency, current mode ■
Low Output Ripple (<20mVP-P Typical)
architecture. Supply current during operation is only
Burst Mode Operation: Only 26μA
26μA, dropping to <1μA in shutdown. The 2.5V to 5.5V ■
Very Low Quiescent Current: Only 26μA
input voltage range makes the LTC3542 ideally suited for ■
2.5V to 5.5V Input Voltage Range
single Li-Ion battery-powered applications. 100% duty ■
2.25MHz Constant Frequency Operation
cycle provides low dropout operation, extending battery ■
1MHz to 3MHz External Frequency Synchronization
life in portable systems. The output voltage is adjustable ■
Low Dropout Operation: 100% Duty Cycle
from 0.6V to VIN. Internal power switches are optimized ■
No Schottky Diode Required
to provide high effi ciency and eliminate the need for an ■ Internal Soft-Start Limits Inrush Current external Schottky diode. ■ 0.6V Reference Allows Low Output Voltages Switching frequency is internally set at 2.25MHz, allowing ■ Shutdown Mode Draws <1μA Supply Current the use of small surface mount inductors and capacitors, ■ ±2% Output Voltage Accuracy and it can synchronize to an external clock signal with a ■ Current Mode Operation for Excellent Line and Load frequency range of 1MHz to 3MHz through the MODE/ Transient Response SYNC pin. The LTC3542 is specifi cally designed to work ■ Overtemperature Protected well with ceramic output capacitors, achieving very low ■ Available in 6-Lead 2mm × 2mm DFN and Small TSOT output voltage ripple and a small PCB footprint. The LTC3542 can be confi gured for the power saving Burst
APPLICATIONS
Mode® Operation. For reduced noise and RF interference, ■ Cellular Telephones the MODE/SYNC pin can be confi gured for pulse skipping ■ Wireless and DSL Modems operation. ■ Digital Cameras ■ MP3 Players , LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■ PDAs and Other Handheld Devices Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885.
Effi ciency and Power Loss vs Output Current TYPICAL APPLICATION
100 1000 VIN = 3.6V 90 VOUT = 1.8V 2.2μH V 80 V OUT IN V 100 IN SW 1.8V 2.7V TO 5.5V POWER LOSS (mW) C 22pF IN 500mA 70 10μF LTC3542 60 CER 150k 50 10 RUN VFB COUT 40 MODE/SYNC 75k 10μF EFFICIENCY (%) CER 30 GND 3542 TA01a 1 20 10 0 0.1 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3542 TA01b 3542fa 1
