Datasheet LTC3547 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Dual Monolithic 300mA Synchronous Step-Down Regulator |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTIO. High Effi ciency Dual Step-Down Outputs: Up to 96%. … |
| File Format / Size | PDF / 310 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. High Effi ciency Dual Step-Down Outputs: Up to 96%. 300mA Output Current per Channel at V. IN = 3V
Model Line for this Datasheet
Text Version of Document
LTC3547 Dual Monolithic 300mA Synchronous Step-Down Regulator
U FEATURES DESCRIPTIO
■
High Effi ciency Dual Step-Down Outputs: Up to 96%
The LTC®3547 is a dual, 2.25MHz, constant-frequency, ■
300mA Output Current per Channel at V
synchronous step-down DC/DC converter in a tiny 3mm
IN = 3V
■
Automatic Low Ripple Burst Mode Operation
× 2mm DFN package. 100% duty cycle provides low drop-
(20mV
out operation, extending battery life in portable systems.
P-P)
■
Only 40µA Quiescent Current During Operation
Low output voltages are supported with the 0.6V feed-
(Both Channels)
back reference voltage. Each regulator can supply 300mA ■
2.25MHz Constant-Frequency Operation
continuous output current. ■
2.5V to 5.5V Input Voltage Range
The input voltage range is 2.5V to 5.5V, making it ideal for ■
Low Dropout Operation: 100% Duty Cycle
Li-Ion and USB powered applications. Supply current dur- ■
Internally Compensated for All Ceramic Capacitors
ing operation is only 40µA and drops to < 1µA in shutdown. ■
Independent Internal Soft-Start for Each Channel
Automatic Burst Mode® operation increases effi ciency at ■ Current Mode Operation for Excellent Line and Load light loads, further extending battery life. Transient Response ■ 0.6V Reference Allows Low Output Voltages An internally set 2.25MHz switching frequency allows ■ Short-Circuit Protected the use of tiny surface mount inductors and capacitors. ■ Ultralow Shutdown Current: I Internal soft-start reduces inrush current during start- Q < 1µA ■ Low Profi le (0.75mm) 8-Lead 3mm up. All outputs are internally compensated to work with × 2mm DFN Package ceramic capacitors. The LTC3547 is available in a low
U
profi le (0.75mm) 3mm × 2mm DFN package. The LTC3547
APPLICATIO S
is also available in a fi xed output voltage confi guration, eliminating the need for the external feedback networks ■ Cellular Telephones (see Table 2). ■ Digital Still Cameras ■ Wireless and DSL Modems , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other ■ PDAs/Palmtop PCs trademarks are the property of their respective owners. Protected by U.S. Patents, including 6580258, 5481178, 6304066, 6127815, 6498466, 6611131. ■ Portable Media Players
U TYPICAL APPLICATIO Effi ciency vs Output Current for VOUT = 2.5V
100 1
Dual Monolithic Buck Regulator in 8-Lead 3mm × 2mm DFN
90 VIN 80 2.5V TO 5.5V 0.1 POWER LOSS (W) 70 4.7µF RUN2 VIN RUN1 60 L2 L1 LTC3547 50 0.01 V 4.7µH 4.7µH OUT2 VOUT1 1.8V AT SW2 SW1 2.5V AT 40 300mA 10pF 10pF 300mA EFFICIENCY (%) 30 0.001 20 VIN = 2.7V VFB2 VFB1 10 VIN = 3.6V 475k GND 475k 4.7µF 237k 150k 4.7µF VIN = 4.2V 0 0.0001 0.1 1 10 100 1000 3547 TA01 OUTPUT CURRENT (mA) 3547 TA01b 3547fa 1
U FEATURES DESCRIPTIO
■
High Effi ciency Dual Step-Down Outputs: Up to 96%
The LTC®3547 is a dual, 2.25MHz, constant-frequency, ■
300mA Output Current per Channel at V
synchronous step-down DC/DC converter in a tiny 3mm
IN = 3V
■
Automatic Low Ripple Burst Mode Operation
× 2mm DFN package. 100% duty cycle provides low drop-
(20mV
out operation, extending battery life in portable systems.
P-P)
■
Only 40µA Quiescent Current During Operation
Low output voltages are supported with the 0.6V feed-
(Both Channels)
back reference voltage. Each regulator can supply 300mA ■
2.25MHz Constant-Frequency Operation
continuous output current. ■
2.5V to 5.5V Input Voltage Range
The input voltage range is 2.5V to 5.5V, making it ideal for ■
Low Dropout Operation: 100% Duty Cycle
Li-Ion and USB powered applications. Supply current dur- ■
Internally Compensated for All Ceramic Capacitors
ing operation is only 40µA and drops to < 1µA in shutdown. ■
Independent Internal Soft-Start for Each Channel
Automatic Burst Mode® operation increases effi ciency at ■ Current Mode Operation for Excellent Line and Load light loads, further extending battery life. Transient Response ■ 0.6V Reference Allows Low Output Voltages An internally set 2.25MHz switching frequency allows ■ Short-Circuit Protected the use of tiny surface mount inductors and capacitors. ■ Ultralow Shutdown Current: I Internal soft-start reduces inrush current during start- Q < 1µA ■ Low Profi le (0.75mm) 8-Lead 3mm up. All outputs are internally compensated to work with × 2mm DFN Package ceramic capacitors. The LTC3547 is available in a low
U
profi le (0.75mm) 3mm × 2mm DFN package. The LTC3547
APPLICATIO S
is also available in a fi xed output voltage confi guration, eliminating the need for the external feedback networks ■ Cellular Telephones (see Table 2). ■ Digital Still Cameras ■ Wireless and DSL Modems , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other ■ PDAs/Palmtop PCs trademarks are the property of their respective owners. Protected by U.S. Patents, including 6580258, 5481178, 6304066, 6127815, 6498466, 6611131. ■ Portable Media Players
U TYPICAL APPLICATIO Effi ciency vs Output Current for VOUT = 2.5V
100 1
Dual Monolithic Buck Regulator in 8-Lead 3mm × 2mm DFN
90 VIN 80 2.5V TO 5.5V 0.1 POWER LOSS (W) 70 4.7µF RUN2 VIN RUN1 60 L2 L1 LTC3547 50 0.01 V 4.7µH 4.7µH OUT2 VOUT1 1.8V AT SW2 SW1 2.5V AT 40 300mA 10pF 10pF 300mA EFFICIENCY (%) 30 0.001 20 VIN = 2.7V VFB2 VFB1 10 VIN = 3.6V 475k GND 475k 4.7µF 237k 150k 4.7µF VIN = 4.2V 0 0.0001 0.1 1 10 100 1000 3547 TA01 OUTPUT CURRENT (mA) 3547 TA01b 3547fa 1
