Datasheet LTC3405A-1.375 (Analog Devices)
| 制造商 | Analog Devices |
| 描述 | 1.375V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT |
| 页数 / 页 | 12 / 1 — FEATURES. DESCRIPTIO. High Efficiency: Up to 90%. Very Low Quiescent … |
| 文件格式/大小 | PDF / 267 Kb |
| 文件语言 | 英语 |
FEATURES. DESCRIPTIO. High Efficiency: Up to 90%. Very Low Quiescent Current: Only 20. During Operation
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LTC3405A-1.375 1.375V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT
U FEATURES DESCRIPTIO
■
High Efficiency: Up to 90%
The LTC®3405A-1.375 is a high efficiency monolithic ■
Very Low Quiescent Current: Only 20
µ
A
synchronous buck regulator using a constant frequency,
During Operation
current mode architecture. Supply current during opera- ■
300mA Output Current at VIN = 3V
tion is only 20µA and drops to <1µA in shutdown. The 2.5V ■
2.5V to 5.5V Input Voltage Range
to 5.5V input voltage range makes the LTC3405A-1.375 ■
1.5MHz Constant Frequency Operation
ideally suited for single Li-Ion battery-powered applica- ■
No Schottky Diode Required
tions. 100% duty cycle provides low dropout operation, ■
Low Dropout Operation: 100% Duty Cycle
extending battery life in portable systems. ■
Stable with Ceramic Capacitors
Switching frequency is internally set at 1.5MHz, allowing ■ Shutdown Mode Draws < 1µA Supply Current the use of small surface mount inductors and capacitors. ■ ±3% Output Voltage Accuracy ■ Current Mode Operation for Excellent Line and The LTC3405A-1.375 is specifically designed to work well Load Transient Response with ceramic output capacitors, achieving very low output ■ Overtemperature Protected voltage ripple and a small PCB footprint. ■ Low Profile (1mm) ThinSOTTM Package The internal synchronous switch increases efficiency and
U
eliminates the need for an external Schottky diode. The
APPLICATIO S
LTC3405A-1.375 is available in a low profile (1mm) ■ Cellular Telephones ThinSOT package. ■ Personal Information Appliances For other output voltages, refer to the LTC3405A and ■ Wireless and DSL Modems LTC3405A-1.5/LTC3405A-1.8 data sheets. ■ Digital Still Cameras , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode ■ MP3 Players is a registered trademark of Linear Technology Corporation. ThinSOT is a trademark of ■ Linear Technology Corporation. All other trademarks are the property of their respective Portable Instruments owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.
U TYPICAL APPLICATIO
100 90 V 4.7µH IN VOUT 80 2.7V VIN SW 1.375V TO 5.5V CIN 300mA 4.7 LTC3405A-1.375 COUT 70 µF CER RUN 4.7µF CER 60 MODE VOUT EFFICIENCY (%) GND 50 3405A1375 F01 VIN = 2.7V V 40 IN = 3.6V VIN = 4.2V VIN = 5.5V 30 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3405A1375 F01b
Figure 1a. High Efficiency Step-Down Converter Figure 1b. Efficiency vs Load Current
3405a1375f 1
U FEATURES DESCRIPTIO
■
High Efficiency: Up to 90%
The LTC®3405A-1.375 is a high efficiency monolithic ■
Very Low Quiescent Current: Only 20
µ
A
synchronous buck regulator using a constant frequency,
During Operation
current mode architecture. Supply current during opera- ■
300mA Output Current at VIN = 3V
tion is only 20µA and drops to <1µA in shutdown. The 2.5V ■
2.5V to 5.5V Input Voltage Range
to 5.5V input voltage range makes the LTC3405A-1.375 ■
1.5MHz Constant Frequency Operation
ideally suited for single Li-Ion battery-powered applica- ■
No Schottky Diode Required
tions. 100% duty cycle provides low dropout operation, ■
Low Dropout Operation: 100% Duty Cycle
extending battery life in portable systems. ■
Stable with Ceramic Capacitors
Switching frequency is internally set at 1.5MHz, allowing ■ Shutdown Mode Draws < 1µA Supply Current the use of small surface mount inductors and capacitors. ■ ±3% Output Voltage Accuracy ■ Current Mode Operation for Excellent Line and The LTC3405A-1.375 is specifically designed to work well Load Transient Response with ceramic output capacitors, achieving very low output ■ Overtemperature Protected voltage ripple and a small PCB footprint. ■ Low Profile (1mm) ThinSOTTM Package The internal synchronous switch increases efficiency and
U
eliminates the need for an external Schottky diode. The
APPLICATIO S
LTC3405A-1.375 is available in a low profile (1mm) ■ Cellular Telephones ThinSOT package. ■ Personal Information Appliances For other output voltages, refer to the LTC3405A and ■ Wireless and DSL Modems LTC3405A-1.5/LTC3405A-1.8 data sheets. ■ Digital Still Cameras , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode ■ MP3 Players is a registered trademark of Linear Technology Corporation. ThinSOT is a trademark of ■ Linear Technology Corporation. All other trademarks are the property of their respective Portable Instruments owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.
U TYPICAL APPLICATIO
100 90 V 4.7µH IN VOUT 80 2.7V VIN SW 1.375V TO 5.5V CIN 300mA 4.7 LTC3405A-1.375 COUT 70 µF CER RUN 4.7µF CER 60 MODE VOUT EFFICIENCY (%) GND 50 3405A1375 F01 VIN = 2.7V V 40 IN = 3.6V VIN = 4.2V VIN = 5.5V 30 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3405A1375 F01b
Figure 1a. High Efficiency Step-Down Converter Figure 1b. Efficiency vs Load Current
3405a1375f 1