Datasheet LTC3803-3 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTION. VIN and VOUT Limited Only by External Components. … |
| File Format / Size | PDF / 179 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. VIN and VOUT Limited Only by External Components. Adjustable Slope Compensation. Internal Soft-Start
Model Line for this Datasheet
Text Version of Document
LTC3803-3 Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT
FEATURES DESCRIPTION
n
VIN and VOUT Limited Only by External Components
The LTC®3803-3 is a constant frequency current mode n
Adjustable Slope Compensation
fl yback controller optimized for driving N-channel MOSFETs n
Internal Soft-Start
in high input voltage applications. Constant frequency n
–55°C to 150°C Operating Temperature Range
operation is maintained down to very light loads, resulting n
Constant Frequency 300kHz Operation
in less low frequency noise generation over a wide range n ±1.5% Reference Accuracy of load currents. Slope compensation can be programmed n Current Mode Operation for Excellent Line and Load with an external resistor. Transient Response The LTC3803-3 provides ±1.5% output voltage accuracy n No Minimum Load Requirement and consumes only 240μA of quiescent current. Ground- n Low Quiescent Current: 240μA referenced current sensing allows LTC3803-3-based con- n Low Profi le (1mm) SOT-23 Package verters to accept input supplies beyond the LTC3803-3’s absolute maximum V
APPLICATIONS
CC. A micropower hysteretic start-up feature allows effi cient operation at high input voltages. For simplicity, the LTC3803-3 can also be powered from a high n Telecom Power Supplies V n IN through a resistor, due to its internal shunt regulator. An 42V and 12V Automotive Power Supplies internal undervoltage lockout shuts down the LTC3803-3 n Auxiliary/Housekeeping Power Supplies when the input voltage is too low to provide suffi cient gate n Power over Ethernet Powered Devices drive to the external MOSFET. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT and No RSENSE are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. The LTC3803-3 is available in a low profi le (1mm) 6-lead SOT-23 (ThinSOT™) package.
TYPICAL APPLICATION 5V Output Nonisolated Telecom Housekeeping Power Supply Effi ciency vs Load Current
V 100 IN V 36V TO 72V OUT = 5V UPS840 95 VOUT T1 5V • 90 1μF 300μF* 2A MAX 10k 100V 6.3V 85 X5R X5R 1μF • 80 10V 75 X5R VCC 70 ITH/RUN NGATE FDC2512 EFFICIENCY (%) 82k 65 LTC3803-3 4.7k 150pF VIN = 36V GND SENSE 200V 60 V 470pF IN = 48V V V FB IN = 60V 68mΩ 220Ω 55 VIN = 72V 50 20k 105k 250 500 750 1000 1250 1500 1750 2000 38033 TA01 LOAD CURRENT (mA) T1: COOPER CTX02-15242 *THREE 100μF UNITS IN PARALLEL 38033 TA02 38033fd 1 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS
FEATURES DESCRIPTION
n
VIN and VOUT Limited Only by External Components
The LTC®3803-3 is a constant frequency current mode n
Adjustable Slope Compensation
fl yback controller optimized for driving N-channel MOSFETs n
Internal Soft-Start
in high input voltage applications. Constant frequency n
–55°C to 150°C Operating Temperature Range
operation is maintained down to very light loads, resulting n
Constant Frequency 300kHz Operation
in less low frequency noise generation over a wide range n ±1.5% Reference Accuracy of load currents. Slope compensation can be programmed n Current Mode Operation for Excellent Line and Load with an external resistor. Transient Response The LTC3803-3 provides ±1.5% output voltage accuracy n No Minimum Load Requirement and consumes only 240μA of quiescent current. Ground- n Low Quiescent Current: 240μA referenced current sensing allows LTC3803-3-based con- n Low Profi le (1mm) SOT-23 Package verters to accept input supplies beyond the LTC3803-3’s absolute maximum V
APPLICATIONS
CC. A micropower hysteretic start-up feature allows effi cient operation at high input voltages. For simplicity, the LTC3803-3 can also be powered from a high n Telecom Power Supplies V n IN through a resistor, due to its internal shunt regulator. An 42V and 12V Automotive Power Supplies internal undervoltage lockout shuts down the LTC3803-3 n Auxiliary/Housekeeping Power Supplies when the input voltage is too low to provide suffi cient gate n Power over Ethernet Powered Devices drive to the external MOSFET. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT and No RSENSE are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. The LTC3803-3 is available in a low profi le (1mm) 6-lead SOT-23 (ThinSOT™) package.
TYPICAL APPLICATION 5V Output Nonisolated Telecom Housekeeping Power Supply Effi ciency vs Load Current
V 100 IN V 36V TO 72V OUT = 5V UPS840 95 VOUT T1 5V • 90 1μF 300μF* 2A MAX 10k 100V 6.3V 85 X5R X5R 1μF • 80 10V 75 X5R VCC 70 ITH/RUN NGATE FDC2512 EFFICIENCY (%) 82k 65 LTC3803-3 4.7k 150pF VIN = 36V GND SENSE 200V 60 V 470pF IN = 48V V V FB IN = 60V 68mΩ 220Ω 55 VIN = 72V 50 20k 105k 250 500 750 1000 1250 1500 1750 2000 38033 TA01 LOAD CURRENT (mA) T1: COOPER CTX02-15242 *THREE 100μF UNITS IN PARALLEL 38033 TA02 38033fd 1 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS
