Datasheet LTC3520 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Synchronous 1A Buck-Boost and 600mA Buck Converters |
| Pages / Page | 24 / 1 — FEATURES. DESCRIPTION. Dual High Effi ciency DC/DC Converters:. … |
| File Format / Size | PDF / 324 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Dual High Effi ciency DC/DC Converters:. Buck-Boost. (VOUT: 2.2V to 5.25V, IOUT = 1A at
Model Line for this Datasheet
Text Version of Document
LTC3520 Synchronous 1A Buck-Boost and 600mA Buck Converters
FEATURES DESCRIPTION
n
Dual High Effi ciency DC/DC Converters:
The LTC®3520 combines 1A buck-boost and 600mA
Buck-Boost (VOUT: 2.2V to 5.25V, IOUT = 1A at
synchronous buck DC/DC converters in a tiny 4mm ×
VOUT = 3.3V, VIN ≥ 3V)
4mm package. A programmable switching frequency
Buck (VOUT: 0.8V to VIN, IOUT = 600mA)
allows the effi ciency to be optimized while minimizing n
2.2V to 5.5V Input Voltage Range
the solution footprint. Both converters feature soft-start n
Pin-Selectable Burst Mode® Operation
and current limit protection. The uncommitted gain block n
Uncommitted Gain Block for LDO Controller, Battery
can be confi gured as an LDO or utilized as a battery-good
Good Indication or Sequencing
comparator. n Programmable 100kHz to 2MHz Switching Frequency The buck converter is current mode controlled with internal n 55μA Total Quiescent Current for Both Converters in synchronous rectifi cation to improve effi ciency. Pin-select- Burst Mode Operation able Burst Mode operation can be enabled to improve light n Thermal and Overcurrent Protection load effi ciency, or the buck converter can be operated in n <1μA Quiescent Current in Shutdown low noise PWM mode for sensitive applications. n 24-Lead 4mm × 4mm QFN Package The buck-boost converter provides continuous conduc-
APPLICATIONS
tion operation to maximize effi ciency and minimize noise. At light loads, use of Burst Mode operation will improve n Portable Media Players effi ciency. n Digital Cameras The LTC3520 provides a <1μA shutdown mode and over- n Handheld PCs, PDAs temperature shutdown on both converters. The LTC3520 n GPS Receivers is available in a low profi le (0.75mm) 24-lead 4mm × L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective 4mm QFN package. owners. Protected by U.S. Patents, including 5481178, 6166527, 6304066, 6404251, 6580258.
TYPICAL APPLICATION 3.3V at 500mA, 1.8V at 600mA and 1.5V at 200mA Converter Effi ciency vs VIN
100 VIN 2.2V TO 4.7μH BUCK-BOOST 22μF 5.5V PV PV PV SV SW1A IN1 IN2 IN3 IN 4.7μH V 95 IOUT = 150mA SW1B OUT1 VOUT2 SW2 VOUT1 3.3V 1.8V 470pF 500mA BUCK 600mA 10μF 255k 27pF V 56pF 47μF 1A FOR 90 C1 IOUT = 250mA V FB2 1M IN ≥ 3V 15k 10k 0.01μF 200k FB1 85 SS2 0.01μF 309k LTC3520 54.9k SS1 EFFICIENCY (%) 80 RT VOUT2 PWM1 AOUT BURST V PWM OUT 75 PWM2 1.5V SD3 200mA 33pF 100k 70 OFF ON SD2 4.7μF 2.2 2.7 3.2 3.7 4.2 4.7 5.2 SD1 AIN V PGND1 SGND PGND2 IN (V) 110k 3520 TA01b 3520 TA01 3520fa 1
FEATURES DESCRIPTION
n
Dual High Effi ciency DC/DC Converters:
The LTC®3520 combines 1A buck-boost and 600mA
Buck-Boost (VOUT: 2.2V to 5.25V, IOUT = 1A at
synchronous buck DC/DC converters in a tiny 4mm ×
VOUT = 3.3V, VIN ≥ 3V)
4mm package. A programmable switching frequency
Buck (VOUT: 0.8V to VIN, IOUT = 600mA)
allows the effi ciency to be optimized while minimizing n
2.2V to 5.5V Input Voltage Range
the solution footprint. Both converters feature soft-start n
Pin-Selectable Burst Mode® Operation
and current limit protection. The uncommitted gain block n
Uncommitted Gain Block for LDO Controller, Battery
can be confi gured as an LDO or utilized as a battery-good
Good Indication or Sequencing
comparator. n Programmable 100kHz to 2MHz Switching Frequency The buck converter is current mode controlled with internal n 55μA Total Quiescent Current for Both Converters in synchronous rectifi cation to improve effi ciency. Pin-select- Burst Mode Operation able Burst Mode operation can be enabled to improve light n Thermal and Overcurrent Protection load effi ciency, or the buck converter can be operated in n <1μA Quiescent Current in Shutdown low noise PWM mode for sensitive applications. n 24-Lead 4mm × 4mm QFN Package The buck-boost converter provides continuous conduc-
APPLICATIONS
tion operation to maximize effi ciency and minimize noise. At light loads, use of Burst Mode operation will improve n Portable Media Players effi ciency. n Digital Cameras The LTC3520 provides a <1μA shutdown mode and over- n Handheld PCs, PDAs temperature shutdown on both converters. The LTC3520 n GPS Receivers is available in a low profi le (0.75mm) 24-lead 4mm × L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective 4mm QFN package. owners. Protected by U.S. Patents, including 5481178, 6166527, 6304066, 6404251, 6580258.
TYPICAL APPLICATION 3.3V at 500mA, 1.8V at 600mA and 1.5V at 200mA Converter Effi ciency vs VIN
100 VIN 2.2V TO 4.7μH BUCK-BOOST 22μF 5.5V PV PV PV SV SW1A IN1 IN2 IN3 IN 4.7μH V 95 IOUT = 150mA SW1B OUT1 VOUT2 SW2 VOUT1 3.3V 1.8V 470pF 500mA BUCK 600mA 10μF 255k 27pF V 56pF 47μF 1A FOR 90 C1 IOUT = 250mA V FB2 1M IN ≥ 3V 15k 10k 0.01μF 200k FB1 85 SS2 0.01μF 309k LTC3520 54.9k SS1 EFFICIENCY (%) 80 RT VOUT2 PWM1 AOUT BURST V PWM OUT 75 PWM2 1.5V SD3 200mA 33pF 100k 70 OFF ON SD2 4.7μF 2.2 2.7 3.2 3.7 4.2 4.7 5.2 SD1 AIN V PGND1 SGND PGND2 IN (V) 110k 3520 TA01b 3520 TA01 3520fa 1
