Datasheet LTC3873-5 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | No RSENSE Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTION. VIN and VOUT Limited Only by External Components. … |
| File Format / Size | PDF / 180 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. VIN and VOUT Limited Only by External Components. Internal or Programmable External Soft-Start
Model Line for this Datasheet
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LTC3873-5 No RSENSETM Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller
FEATURES DESCRIPTION
n
VIN and VOUT Limited Only by External Components
The LTC®3873-5 is a constant frequency current mode n
Internal or Programmable External Soft-Start
controller for boost, fl yback or SEPIC DC/DC converters n
Constant Frequency 200kHz Operation
designed to drive an N-channel MOSFET for high input n
Adjustable Current Limit
and output voltage converter applications. n
Current Sense Resistor Optional
The LTC3873-5 provides ±1.5% output voltage accuracy n ±1.5% Voltage Reference Accuracy and consumes only 300μA quiescent current during nor- n Current Mode Operation for Excellent Line and Load mal operation and only 50μA during micropower start-up. Transient Response Using a 9.3V internal shunt regulator, the LTC3873-5 can n 4.1V Undervoltage Threshold for Logic Level be powered from a high input voltage through a resistor MOSFET Applications or it can be powered directly from a low impedance DC n Low Quiescent Current: 300μA voltage of 9V or less. Soft-start can be programmed using n Low Profi le (1mm) ThinSOTTM and (0.75mm) an external capacitor. 2mm × 3mm DFN Package The LTC3873-5 is available in 8-lead ThinSOT and 2mm
APPLICATIONS
× 3mm DFN packages. n
PARAMETER LTC3873 LTC3873-5
Telecom Power Supplies V n Automotive Power Supplies CC UV+ 8.4V 4.1V VCC UV– 4V 2.9V n PoE Applications L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No RSENSE and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION High Effi ciency 5V Input, 12V Output Boost Converter Effi ciency and Power Loss vs Load Current
100 10000 1nF 90 4.7nF RUN/SS 11.8k 80 V I IN POWER LOSS (mW) TH VCC 5V 70 47pF 1000 LTC3873-5 10μF 10μH 60 IPRG V 50 OUT GND SW 12V 12k 40 2A EFFICIENCY (%) V 100 FB NGATE 22μF 30 108k 20 38735 TA01a 10 0 10 10 100 1000 IOUT (mA) 3873 TA01b 38735fb 1
FEATURES DESCRIPTION
n
VIN and VOUT Limited Only by External Components
The LTC®3873-5 is a constant frequency current mode n
Internal or Programmable External Soft-Start
controller for boost, fl yback or SEPIC DC/DC converters n
Constant Frequency 200kHz Operation
designed to drive an N-channel MOSFET for high input n
Adjustable Current Limit
and output voltage converter applications. n
Current Sense Resistor Optional
The LTC3873-5 provides ±1.5% output voltage accuracy n ±1.5% Voltage Reference Accuracy and consumes only 300μA quiescent current during nor- n Current Mode Operation for Excellent Line and Load mal operation and only 50μA during micropower start-up. Transient Response Using a 9.3V internal shunt regulator, the LTC3873-5 can n 4.1V Undervoltage Threshold for Logic Level be powered from a high input voltage through a resistor MOSFET Applications or it can be powered directly from a low impedance DC n Low Quiescent Current: 300μA voltage of 9V or less. Soft-start can be programmed using n Low Profi le (1mm) ThinSOTTM and (0.75mm) an external capacitor. 2mm × 3mm DFN Package The LTC3873-5 is available in 8-lead ThinSOT and 2mm
APPLICATIONS
× 3mm DFN packages. n
PARAMETER LTC3873 LTC3873-5
Telecom Power Supplies V n Automotive Power Supplies CC UV+ 8.4V 4.1V VCC UV– 4V 2.9V n PoE Applications L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No RSENSE and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION High Effi ciency 5V Input, 12V Output Boost Converter Effi ciency and Power Loss vs Load Current
100 10000 1nF 90 4.7nF RUN/SS 11.8k 80 V I IN POWER LOSS (mW) TH VCC 5V 70 47pF 1000 LTC3873-5 10μF 10μH 60 IPRG V 50 OUT GND SW 12V 12k 40 2A EFFICIENCY (%) V 100 FB NGATE 22μF 30 108k 20 38735 TA01a 10 0 10 10 100 1000 IOUT (mA) 3873 TA01b 38735fb 1
