Datasheet LTC3563 (Analog Devices)
| 制造商 | Analog Devices |
| 描述 | 500mA, Synchronous Step-Down DC/DC Converter with Selectable Output Voltage |
| 页数 / 页 | 16 / 1 — FEATURES. DESCRIPTIO. High Effi ciency: Up to 96%. Pin Selectable Output … |
| 文件格式/大小 | PDF / 288 Kb |
| 文件语言 | 英语 |
FEATURES. DESCRIPTIO. High Effi ciency: Up to 96%. Pin Selectable Output Voltage: 1.28V/1.87V. Low Ripple (<20mV
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LTC3563 500mA, Synchronous Step-Down DC/DC Converter with Selectable Output Voltage
U FEATURES DESCRIPTIO
■
High Effi ciency: Up to 96%
The LTC®3563 is a high effi ciency monolithic synchro- ■
Pin Selectable Output Voltage: 1.28V/1.87V
nous buck converter using a constant frequency, current ■
Low Ripple (<20mV
mode architecture. A voltage select input allows the user
P-P) Burst Mode® Operation: I
to program the output voltage to 1.28V or 1.87V. Supply
Q = 26µA
■
Very Low Quiescent Current: Only 26µA
current during operation is only 26µA, dropping to <1µA in ■
2.5V to 5.5V Input Voltage Range
shutdown. The 2.5V to 5.5V input voltage range makes the ■
2.25MHz Constant Frequency Operation
LTC3563 ideally suited for single Li-Ion battery-powered ■
Low Dropout Operation: 100% Duty Cycle
applications. 100% duty cycle provides low dropout opera- ■
No Schottky Diode Required
tion, extending battery life in portable systems. Internal ■ Internal Soft-Start Limits Inrush Current power switches are optimized to provide high effi ciency ■ Shutdown Mode Draws <1µA Supply Current and eliminate the need for an external Schottky diode. ■ ±2% Output Voltage Accuracy The switching frequency is internally set at 2.25MHz, ■ Current Mode Operation for Excellent Line and Load allowing the use of small surface mount inductors and Transient Response capacitors. The LTC3563 is specifi cally designed to work ■ Overtemperature Protected well with ceramic output capacitors, achieving very low ■ Available in 2mm × 2mm 6-Lead DFN output voltage ripple and a small PCB footprint.
U APPLICATIO S
The LTC3563 is confi gured for the power saving Burst Mode Operation. ■ Cellular Telephones , LTC, LT, LTM and Burst Mode are registered trademarks of Linear Technology ■ Wireless and DSL Modems Corporation. All other trademarks are the property of their respective owners. ■ Digital Cameras Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885. ■ MP3 Players ■ PDAs and Other Handheld Devices
U TYPICAL APPLICATIO Effi ciency and Power Loss vs Output Current
100 1000 90 2.2µH V V OUT 80 IN VIN SW 1.28V/1.87V 2.7V TO 5.5V 100 C POWER LOSS (mW) IN 500mA 70 10µF LTC3563 CER 60 RUN VOUT COUT 10µF 50 10 1.28V 1.87V V CER SEL 40 3563 TA01a EFFICIENCY (%) GND 30 1 20 10 VIN = 3.6V VOUT = 1.87V 0 0.1 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3563 TA01b 3563f 1
U FEATURES DESCRIPTIO
■
High Effi ciency: Up to 96%
The LTC®3563 is a high effi ciency monolithic synchro- ■
Pin Selectable Output Voltage: 1.28V/1.87V
nous buck converter using a constant frequency, current ■
Low Ripple (<20mV
mode architecture. A voltage select input allows the user
P-P) Burst Mode® Operation: I
to program the output voltage to 1.28V or 1.87V. Supply
Q = 26µA
■
Very Low Quiescent Current: Only 26µA
current during operation is only 26µA, dropping to <1µA in ■
2.5V to 5.5V Input Voltage Range
shutdown. The 2.5V to 5.5V input voltage range makes the ■
2.25MHz Constant Frequency Operation
LTC3563 ideally suited for single Li-Ion battery-powered ■
Low Dropout Operation: 100% Duty Cycle
applications. 100% duty cycle provides low dropout opera- ■
No Schottky Diode Required
tion, extending battery life in portable systems. Internal ■ Internal Soft-Start Limits Inrush Current power switches are optimized to provide high effi ciency ■ Shutdown Mode Draws <1µA Supply Current and eliminate the need for an external Schottky diode. ■ ±2% Output Voltage Accuracy The switching frequency is internally set at 2.25MHz, ■ Current Mode Operation for Excellent Line and Load allowing the use of small surface mount inductors and Transient Response capacitors. The LTC3563 is specifi cally designed to work ■ Overtemperature Protected well with ceramic output capacitors, achieving very low ■ Available in 2mm × 2mm 6-Lead DFN output voltage ripple and a small PCB footprint.
U APPLICATIO S
The LTC3563 is confi gured for the power saving Burst Mode Operation. ■ Cellular Telephones , LTC, LT, LTM and Burst Mode are registered trademarks of Linear Technology ■ Wireless and DSL Modems Corporation. All other trademarks are the property of their respective owners. ■ Digital Cameras Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885. ■ MP3 Players ■ PDAs and Other Handheld Devices
U TYPICAL APPLICATIO Effi ciency and Power Loss vs Output Current
100 1000 90 2.2µH V V OUT 80 IN VIN SW 1.28V/1.87V 2.7V TO 5.5V 100 C POWER LOSS (mW) IN 500mA 70 10µF LTC3563 CER 60 RUN VOUT COUT 10µF 50 10 1.28V 1.87V V CER SEL 40 3563 TA01a EFFICIENCY (%) GND 30 1 20 10 VIN = 3.6V VOUT = 1.87V 0 0.1 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3563 TA01b 3563f 1