Datasheet LT3970 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 40V, 350mA Step-Down Regulator with 2.5μA Quiescent Current and Integrated Diodes |
| Pages / Page | 22 / 1 — FeaTures. DescripTion. Low Ripple Burst Mode. Operation. 2.5µA. IQ at … |
| File Format / Size | PDF / 330 Kb |
| Document Language | English |
FeaTures. DescripTion. Low Ripple Burst Mode. Operation. 2.5µA. IQ at 12VIN to 3.3VOUT. Output Ripple < 5mVP-P
Model Line for this Datasheet
LT3970 Series
Text Version of Document
LT3970 Series 40V, 350mA Step-Down Regulator with 2.5µA Quiescent Current and Integrated Diodes
FeaTures DescripTion
n
Low Ripple Burst Mode
®
Operation
The LT®3970 is an adjustable frequency monolithic buck
2.5µA IQ at 12VIN to 3.3VOUT
switching regulator that accepts a wide input voltage
Output Ripple < 5mVP-P
range up to 40V, and consumes only 2.5µA of quiescent n
Wide Input Voltage Range: 4.2V to 40V Operating
current. A high efficiency switch is included on the die n
Adjustable Switching Frequency: 200kHz to 2.2MHz
along with the catch diode, boost diode, and the neces- n
Integrated Boost and Catch Diodes
sary oscillator, control and logic circuitry. Low ripple Burst n
350mA Output Current
Mode operation maintains high efficiency at low output n
Fixed Output Voltages: 3.3V, 3.42V, 5V
currents while keeping the output ripple below 5mV in a
1.8µA IQ at 12VIN
typical application. Current mode topology is used for fast n Accurate 1V Enable Pin Threshold transient response and good loop stability. A catch diode n Low Shutdown Current: IQ = 0.7µA current limit provides protection against shorted outputs n Internal Sense Limits Catch Diode Current and overvoltage conditions. An enable pin with accurate n Power Good Flag threshold is available, producing a low shutdown current n Output Voltage: 1.21V to 25V of 0.7µA. A power good flag signals when VOUT reaches n Internal Compensation 90% of the programmed output voltage. The LT3970 is n Small 10-Pin MSOP and (3mm × 2mm) DFN Packages available in small 10-pin MSOP and 3mm × 2mm DFN packages.
applicaTions
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Automotive Battery Regulation n Power for Portable Products n Industrial Supplies
Typical applicaTion 5V Step-Down Converter Efficiency
90 1000 VIN VIN = 12V 6V TO 40V 0.22µF V 80 100 IN BOOST POWER LOSS (mW) LT3970 22µH VOUT OFF ON EN SW 5V 70 10 PG 350mA BD 22pF 1M 60 1 2.2µF RT FB 22µF EFFICIENCY (%) GND 226k 316k 50 0.1 f = 600kHz 3490 TA01a 40 0.01 0.01 0.1 1 10 100 LOAD CURRENT (mA) 3970 TA01b 3970fc 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Related Parts
FeaTures DescripTion
n
Low Ripple Burst Mode
®
Operation
The LT®3970 is an adjustable frequency monolithic buck
2.5µA IQ at 12VIN to 3.3VOUT
switching regulator that accepts a wide input voltage
Output Ripple < 5mVP-P
range up to 40V, and consumes only 2.5µA of quiescent n
Wide Input Voltage Range: 4.2V to 40V Operating
current. A high efficiency switch is included on the die n
Adjustable Switching Frequency: 200kHz to 2.2MHz
along with the catch diode, boost diode, and the neces- n
Integrated Boost and Catch Diodes
sary oscillator, control and logic circuitry. Low ripple Burst n
350mA Output Current
Mode operation maintains high efficiency at low output n
Fixed Output Voltages: 3.3V, 3.42V, 5V
currents while keeping the output ripple below 5mV in a
1.8µA IQ at 12VIN
typical application. Current mode topology is used for fast n Accurate 1V Enable Pin Threshold transient response and good loop stability. A catch diode n Low Shutdown Current: IQ = 0.7µA current limit provides protection against shorted outputs n Internal Sense Limits Catch Diode Current and overvoltage conditions. An enable pin with accurate n Power Good Flag threshold is available, producing a low shutdown current n Output Voltage: 1.21V to 25V of 0.7µA. A power good flag signals when VOUT reaches n Internal Compensation 90% of the programmed output voltage. The LT3970 is n Small 10-Pin MSOP and (3mm × 2mm) DFN Packages available in small 10-pin MSOP and 3mm × 2mm DFN packages.
applicaTions
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Automotive Battery Regulation n Power for Portable Products n Industrial Supplies
Typical applicaTion 5V Step-Down Converter Efficiency
90 1000 VIN VIN = 12V 6V TO 40V 0.22µF V 80 100 IN BOOST POWER LOSS (mW) LT3970 22µH VOUT OFF ON EN SW 5V 70 10 PG 350mA BD 22pF 1M 60 1 2.2µF RT FB 22µF EFFICIENCY (%) GND 226k 316k 50 0.1 f = 600kHz 3490 TA01a 40 0.01 0.01 0.1 1 10 100 LOAD CURRENT (mA) 3970 TA01b 3970fc 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Related Parts
