Datasheet LTC3822 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | No RSENSE , Low Input Voltage, Synchronous Step-Down DC/DC Controller |
| Pages / Page | 20 / 1 — FEATURES. DESCRIPTION. No Current Sense Resistor Required. All N-Channel … |
| File Format / Size | PDF / 209 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. No Current Sense Resistor Required. All N-Channel MOSFET Synchronous Drive
Model Line for this Datasheet
Text Version of Document
LTC3822 No RSENSE™, Low Input Voltage, Synchronous Step-Down DC/DC Controller
FEATURES DESCRIPTION
n
No Current Sense Resistor Required
The LTC®3822 is a synchronous step-down switching n
All N-Channel MOSFET Synchronous Drive
regulator controller that drives external N-channel power n
High Current Outputs Possible
MOSFETs using few external components. The constant n Constant Frequency Current Mode Operation for frequency current mode architecture with MOSFET VDS Excellent Line and Load Transient Response sensing eliminates the need for sense resistors and im- n VIN: 2.75V to 4.5V proves effi ciency. n ±1% 0.6V Reference A maximum duty cycle of 99% provides low dropout n Low Dropout Operation: 99% Duty Cycle operation. The switching frequency can be programmed n Selectable Frequency (300kHz/550kHz/750kHz) up to 750kHz, allowing the use of small surface mount n Internal Soft-Start Circuitry inductors and capacitors. n Selectable Maximum Peak Current Sense Threshold n Digital RUN Control Pin The LTC3822 is available in thermally enhanced DFN and n Output Overvoltage Protection 10-lead MSOP packages. n Micropower Shutdown: IQ = 7.5μA L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No R n SENSE is a trademark of Linear Technology Corporation. All other trademarks are the Tiny Thermally Enhanced Leadless (3mm × 3mm) property of their respective owners. Protected by U.S. Patents, including 5481178, 5929620, 6580258, 6304066, 5847554, 6611131, 6498466. DFN or 10-Lead MSOP Package
APPLICATIONS
n 3.3VIN Systems n Li-Ion Battery Systems
TYPICAL APPLICATION 1.8V/8A High Effi ciency, 550kHz Step-Down Converter Effi ciency and Power Loss vs Load Current
100 10 VIN V IPRG V IN = 3.3V IN 2.75V TO 4.5V 90 47μF EFFICIENCY RUN 80 TG FDS6898A 70 POWER LOSS (W) FREQ 1 SW 0.47μH V LTC3822 OUT 60 I 0.22μF TH 1.8V 50 8A 5.1k BOOST 100μF 40 EFFICIENCY (%) 680pF POWER LOSS 0.1 30 GND BG 20 VFB 10 59k 118k 0 0.01 100 1000 10000 3822 TA01 LOAD CURRENT (mA) 3822 TA01b 3822fa 1
FEATURES DESCRIPTION
n
No Current Sense Resistor Required
The LTC®3822 is a synchronous step-down switching n
All N-Channel MOSFET Synchronous Drive
regulator controller that drives external N-channel power n
High Current Outputs Possible
MOSFETs using few external components. The constant n Constant Frequency Current Mode Operation for frequency current mode architecture with MOSFET VDS Excellent Line and Load Transient Response sensing eliminates the need for sense resistors and im- n VIN: 2.75V to 4.5V proves effi ciency. n ±1% 0.6V Reference A maximum duty cycle of 99% provides low dropout n Low Dropout Operation: 99% Duty Cycle operation. The switching frequency can be programmed n Selectable Frequency (300kHz/550kHz/750kHz) up to 750kHz, allowing the use of small surface mount n Internal Soft-Start Circuitry inductors and capacitors. n Selectable Maximum Peak Current Sense Threshold n Digital RUN Control Pin The LTC3822 is available in thermally enhanced DFN and n Output Overvoltage Protection 10-lead MSOP packages. n Micropower Shutdown: IQ = 7.5μA L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No R n SENSE is a trademark of Linear Technology Corporation. All other trademarks are the Tiny Thermally Enhanced Leadless (3mm × 3mm) property of their respective owners. Protected by U.S. Patents, including 5481178, 5929620, 6580258, 6304066, 5847554, 6611131, 6498466. DFN or 10-Lead MSOP Package
APPLICATIONS
n 3.3VIN Systems n Li-Ion Battery Systems
TYPICAL APPLICATION 1.8V/8A High Effi ciency, 550kHz Step-Down Converter Effi ciency and Power Loss vs Load Current
100 10 VIN V IPRG V IN = 3.3V IN 2.75V TO 4.5V 90 47μF EFFICIENCY RUN 80 TG FDS6898A 70 POWER LOSS (W) FREQ 1 SW 0.47μH V LTC3822 OUT 60 I 0.22μF TH 1.8V 50 8A 5.1k BOOST 100μF 40 EFFICIENCY (%) 680pF POWER LOSS 0.1 30 GND BG 20 VFB 10 59k 118k 0 0.01 100 1000 10000 3822 TA01 LOAD CURRENT (mA) 3822 TA01b 3822fa 1
