Datasheet LTC3544 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTION. High Effi ciency: Up to 95%. Four Independent … |
| File Format / Size | PDF / 300 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. High Effi ciency: Up to 95%. Four Independent Regulators Provide Up to 300mA,
Model Line for this Datasheet
Text Version of Document
LTC3544 Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA
FEATURES DESCRIPTION
■
High Effi ciency: Up to 95%
The LTC®3544 is a quad, high efficiency, monolithic ■
Four Independent Regulators Provide Up to 300mA,
synchronous buck regulator using a constant-frequency,
200mA, 200mA and 100mA Output Current
current mode architecture. The four regulators operate ■
2.25V to 5.5V Input Voltage Range
independently with separate run pins. The 2.25V to 5.5V ■
2.25MHz Constant-Frequency Operation
input voltage range makes the LTC3544 well suited for ■
No Schottky Diodes Required
single Li-Ion/polymer battery-powered applications. ■
Extremely Low Channel-to-Channel Transient
100% duty cycle provides low dropout operation, ex-
Crosstalk
tending battery runtime in portable systems. Low ripple ■
Low Ripple (20mVP-P) Burst Mode Operation:
Burst Mode® operation increases effi ciency at light loads,
IQ = 70μA (All Channels On)
further extending battery runtime with typically only 20mV ■ 0.8V Reference Allows Low Output Voltages of ripple. ■ Shutdown Mode Draws <1μA Supply Current Switching frequency is internally set to 2.25MHz, allowing ■ Current Mode Operation for Excellent Line and Load the use of small surface mount inductors and capacitors. Transient Response The internal synchronous switches increase effi ciency ■ Overtemperature Protected and eliminate the need for external Schottky diodes. Low ■ Low Profi le (3mm × 3mm) 16-Lead QFN Package output voltages are easily supported with the 0.8V feedback reference voltage.
APPLICATIONS
The LTC3544 is available in a low profi le (0.75mm) (3mm ■ Cellular Telephones × 3mm) QFN package. ■ Personal Information Appliances , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ Wireless and DSL Modems Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, ■ Digital Still Cameras including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885. ■ Media Players ■ Portable Instruments
TYPICAL APPLICATION Effi ciency vs Load Current, 300mA High Effi ciency Quad Step-Down Converter Channel, All Other Channels Off
100 1 VIN 2.25V TO 5.5V 4.7μF 90 CER VCC PVIN EFFICIENCY 80 V RUN200B RUN200A OUT2 4.7μH 3.3μH VOUT3 0.1 1.5V POWER LOSS (W) SW200B SW200A 0.8V 70 200mA 93.1k 200mA LOSS V 60 FB200B VFB200A 4.7μF 4.7μF 107k 100k 50 VOUT = 2.5V 0.01 CER CER T LTC3544 A = 25°C 40 EFFICIENCY (%) 30 RUN300 RUN100 V 3.3 0.001 OUT4 μH 10μH VOUT1 20 1.8V SW300 SW100 1.2V VIN = 2.7V 133k 59k 300mA 100mA 10 VIN = 3.6V VFB300 VFB100 VIN = 4.2V 4.7μF GNDA PGND 4.7μF 0 0.0001 107k 118k CER CER 0.0001 0.001 0.01 0.1 1 LOAD CURRENT (A) 3544 TA01b 3544B TA01a 3544fa 1
FEATURES DESCRIPTION
■
High Effi ciency: Up to 95%
The LTC®3544 is a quad, high efficiency, monolithic ■
Four Independent Regulators Provide Up to 300mA,
synchronous buck regulator using a constant-frequency,
200mA, 200mA and 100mA Output Current
current mode architecture. The four regulators operate ■
2.25V to 5.5V Input Voltage Range
independently with separate run pins. The 2.25V to 5.5V ■
2.25MHz Constant-Frequency Operation
input voltage range makes the LTC3544 well suited for ■
No Schottky Diodes Required
single Li-Ion/polymer battery-powered applications. ■
Extremely Low Channel-to-Channel Transient
100% duty cycle provides low dropout operation, ex-
Crosstalk
tending battery runtime in portable systems. Low ripple ■
Low Ripple (20mVP-P) Burst Mode Operation:
Burst Mode® operation increases effi ciency at light loads,
IQ = 70μA (All Channels On)
further extending battery runtime with typically only 20mV ■ 0.8V Reference Allows Low Output Voltages of ripple. ■ Shutdown Mode Draws <1μA Supply Current Switching frequency is internally set to 2.25MHz, allowing ■ Current Mode Operation for Excellent Line and Load the use of small surface mount inductors and capacitors. Transient Response The internal synchronous switches increase effi ciency ■ Overtemperature Protected and eliminate the need for external Schottky diodes. Low ■ Low Profi le (3mm × 3mm) 16-Lead QFN Package output voltages are easily supported with the 0.8V feedback reference voltage.
APPLICATIONS
The LTC3544 is available in a low profi le (0.75mm) (3mm ■ Cellular Telephones × 3mm) QFN package. ■ Personal Information Appliances , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ Wireless and DSL Modems Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, ■ Digital Still Cameras including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885. ■ Media Players ■ Portable Instruments
TYPICAL APPLICATION Effi ciency vs Load Current, 300mA High Effi ciency Quad Step-Down Converter Channel, All Other Channels Off
100 1 VIN 2.25V TO 5.5V 4.7μF 90 CER VCC PVIN EFFICIENCY 80 V RUN200B RUN200A OUT2 4.7μH 3.3μH VOUT3 0.1 1.5V POWER LOSS (W) SW200B SW200A 0.8V 70 200mA 93.1k 200mA LOSS V 60 FB200B VFB200A 4.7μF 4.7μF 107k 100k 50 VOUT = 2.5V 0.01 CER CER T LTC3544 A = 25°C 40 EFFICIENCY (%) 30 RUN300 RUN100 V 3.3 0.001 OUT4 μH 10μH VOUT1 20 1.8V SW300 SW100 1.2V VIN = 2.7V 133k 59k 300mA 100mA 10 VIN = 3.6V VFB300 VFB100 VIN = 4.2V 4.7μF GNDA PGND 4.7μF 0 0.0001 107k 118k CER CER 0.0001 0.001 0.01 0.1 1 LOAD CURRENT (A) 3544 TA01b 3544B TA01a 3544fa 1
