Datasheet LTC3405A-1.5, LTC3405A-1.8 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | 1.8V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT |
| Seiten / Seite | 16 / 1 — FEATURES. DESCRIPTIO. High Efficiency: Up to 93%. Very Low Quiescent … |
| Dateiformat / Größe | PDF / 209 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTIO. High Efficiency: Up to 93%. Very Low Quiescent Current: Only 20. During Operation
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LTC3405A-1.5/LTC3405A-1.8 1.5V, 1.8V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT
U FEATURES DESCRIPTIO
■
High Efficiency: Up to 93%
The LTC®3405A-1.5/LTC3405A-1.8 are high efficiency ■
Very Low Quiescent Current: Only 20
µ
A
monolithic synchronous buck regulators using a constant
During Operation
frequency, current mode architecture. Supply current ■
300mA Output Current at VIN = 3V
during operation is only 20µA and drops to <1µA in ■
2.5V to 5.5V Input Voltage Range
shutdown. The 2.5V to 5.5V input voltage range makes the ■
1.5MHz Constant Frequency Operation
LTC3405A-1.5/LTC3405A-1.8 ideally suited for single ■
No Schottky Diode Required
Li-Ion battery-powered applications. 100% duty cycle ■
Low Dropout Operation: 100% Duty Cycle
provides low dropout operation, extending battery life in ■
Stable with Ceramic Capacitors
portable systems. ■ Shutdown Mode Draws < 1µA Supply Current Switching frequency is internally set at 1.5MHz, allowing ■ ±3% Output Voltage Accuracy the use of small surface mount inductors and capacitors. ■ Current Mode Operation for Excellent Line and Load Transient Response The LTC3405A-1.5/LTC3405A-1.8 are specifically designed ■ Overtemperature Protected to work well with ceramic output capacitors, achieving ■ Low Profile (1mm) ThinSOTTM Package very low output voltage ripple and a small PCB footprint.
U
The internal synchronous switch increases efficiency and
APPLICATIO S
eliminates the need for an external Schottky diode. The ■ Cellular Telephones LTC3405A-1.5/LTC3405A-1.8 are available in a low profile ■ Personal Information Appliances (1mm) ThinSOT package. ■ Wireless and DSL Modems For adjustable output voltage, refer to the LTC3405A data ■ Digital Still Cameras sheet. ■ MP3 Players , LTC and LT are registered trademarks of Linear Technology Corporation. ■ Portable Instruments ThinSOT is a trademark of Linear Technology Corporation. Protected by U.S. Patents, including 6580258, 5481178.
U TYPICAL APPLICATIO
100 VIN = 2.7V 90 V 4.7µH* IN V 4 3 OUT 2.7V V 80 V IN SW 1.8V IN = 3.6V TO 5.5V CIN** 300mA V 4.7 IN = 4.2V µF LTC3405A-1.8 COUT** 1 70 CER RUN 4.7µF VIN = 5.5V 6 5 CER MODE VOUT EFFICIENCY (%) 60 GND 3405A1518 F01 2 50 *MURATA LQH3C4R7M34 40 **TAIYO YUDEN JMK212BJ475MG 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3405A1518 F01b
Figure 1a. High Efficiency Step-Down Converter Figure 1b. Efficiency vs Load Current
3405a1518fa 1
U FEATURES DESCRIPTIO
■
High Efficiency: Up to 93%
The LTC®3405A-1.5/LTC3405A-1.8 are high efficiency ■
Very Low Quiescent Current: Only 20
µ
A
monolithic synchronous buck regulators using a constant
During Operation
frequency, current mode architecture. Supply current ■
300mA Output Current at VIN = 3V
during operation is only 20µA and drops to <1µA in ■
2.5V to 5.5V Input Voltage Range
shutdown. The 2.5V to 5.5V input voltage range makes the ■
1.5MHz Constant Frequency Operation
LTC3405A-1.5/LTC3405A-1.8 ideally suited for single ■
No Schottky Diode Required
Li-Ion battery-powered applications. 100% duty cycle ■
Low Dropout Operation: 100% Duty Cycle
provides low dropout operation, extending battery life in ■
Stable with Ceramic Capacitors
portable systems. ■ Shutdown Mode Draws < 1µA Supply Current Switching frequency is internally set at 1.5MHz, allowing ■ ±3% Output Voltage Accuracy the use of small surface mount inductors and capacitors. ■ Current Mode Operation for Excellent Line and Load Transient Response The LTC3405A-1.5/LTC3405A-1.8 are specifically designed ■ Overtemperature Protected to work well with ceramic output capacitors, achieving ■ Low Profile (1mm) ThinSOTTM Package very low output voltage ripple and a small PCB footprint.
U
The internal synchronous switch increases efficiency and
APPLICATIO S
eliminates the need for an external Schottky diode. The ■ Cellular Telephones LTC3405A-1.5/LTC3405A-1.8 are available in a low profile ■ Personal Information Appliances (1mm) ThinSOT package. ■ Wireless and DSL Modems For adjustable output voltage, refer to the LTC3405A data ■ Digital Still Cameras sheet. ■ MP3 Players , LTC and LT are registered trademarks of Linear Technology Corporation. ■ Portable Instruments ThinSOT is a trademark of Linear Technology Corporation. Protected by U.S. Patents, including 6580258, 5481178.
U TYPICAL APPLICATIO
100 VIN = 2.7V 90 V 4.7µH* IN V 4 3 OUT 2.7V V 80 V IN SW 1.8V IN = 3.6V TO 5.5V CIN** 300mA V 4.7 IN = 4.2V µF LTC3405A-1.8 COUT** 1 70 CER RUN 4.7µF VIN = 5.5V 6 5 CER MODE VOUT EFFICIENCY (%) 60 GND 3405A1518 F01 2 50 *MURATA LQH3C4R7M34 40 **TAIYO YUDEN JMK212BJ475MG 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3405A1518 F01b
Figure 1a. High Efficiency Step-Down Converter Figure 1b. Efficiency vs Load Current
3405a1518fa 1