Datasheet LT3973, LT3973-3.3, LT3973-5 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 42V, 750mA Step-Down Regulator with 2.5μA Quiescent Current and Integrated Diodes |
| Pages / Page | 24 / 1 — FEATURES. DESCRIPTION. Ultralow Quiescent Current. 2.5µA IQ at 12VIN to … |
| File Format / Size | PDF / 479 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Ultralow Quiescent Current. 2.5µA IQ at 12VIN to 3.3VOUT. Low Ripple Burst Mode. Operation
Model Line for this Datasheet
- LT3973EDD#PBF LT3973EDD#TRPBF LT3973EDD-3.3#PBF LT3973EDD-3.3#TRPBF LT3973EDD-5#PBF LT3973EDD-5#TRPBF LT3973EMSE#PBF LT3973EMSE#TRPBF LT3973EMSE-3.3#PBF LT3973EMSE-3.3#TRPBF LT3973EMSE-5#PBF LT3973EMSE-5#TRPBF LT3973HDD#PBF LT3973HDD#TRPBF LT3973HDD-3.3#PBF LT3973HDD-3.3#TRPBF LT3973HDD-5#PBF LT3973HDD-5#TRPBF LT3973HMSE#PBF LT3973HMSE#TRPBF LT3973HMSE-3.3#PBF LT3973HMSE-3.3#TRPBF LT3973HMSE-5#PBF LT3973HMSE-5#TRPBF LT3973IDD#PBF LT3973IDD#TRPBF LT3973IDD-3.3#PBF LT3973IDD-3.3#TRPBF LT3973IDD-5#PBF LT3973IDD-5#TRPBF LT3973IMSE#PBF LT3973IMSE#TRPBF LT3973IMSE-3.3#PBF LT3973IMSE-3.3#TRPBF LT3973IMSE-5#PBF LT3973IMSE-5#TRPBF
Text Version of Document
LT3973/LT3973-3.3/LT3973-5 42V, 750mA Step-Down Regulator with 2.5µA Quiescent Current and Integrated Diodes
FEATURES DESCRIPTION
n
Ultralow Quiescent Current
The LT®3973 is an adjustable frequency monolithic buck n
2.5µA IQ at 12VIN to 3.3VOUT
switching regulator that accepts a wide input voltage range n
Low Ripple Burst Mode
®
Operation
up to 42V, and consumes only 2.5µA of quiescent current. n
Output Ripple < 10mVP-P
A high efficiency switch is included on the die along with n
Wide Input Voltage Range: 4.2V to 42V Operating
the catch diode, boost diode, and the necessary oscillator, n
Adjustable Switching Frequency: 200kHz to 2.2MHz
control and logic circuitry. Low ripple Burst Mode operation n
Integrated Boost and Catch Diodes
maintains high efficiency at low output currents while keep- n
750mA Output Current
ing the output ripple below 10mV in a typical application. n
Excellent Start-Up and Dropout Performance
A minimum dropout voltage of 530mV is maintained when n
Fixed Output Voltages: 3.3V, 5V
the input voltage drops below the programmed output volt- n
1.9µA I
age, such as during automotive cold crank. Current mode
Q at 12VIN
n topology is used for fast transient response and good loop Accurate Programmable Undervoltage Lockout n stability. A catch diode current limit provides protection Low Shutdown Current: IQ = 0.75µA n against shorted outputs and overvoltage conditions, with Internal Catch Diode Current Limit n thermal shutdown providing additional fault protection. An Power Good Flag n accurate programmable undervoltage lockout feature is Thermal Shutdown n available, producing a low shutdown current of 0.75µA. Small, Thermally Enhanced 10-Lead MSOP and A power good flag signals when VOUT reaches 90% of (3mm × 3mm) DFN Packages the programmed output voltage. The LT3973 is available
APPLICATIONS
in small, thermally enhanced 10-lead MSOP and 3mm × 3mm DFN packages. n Automotive Battery Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Power for Portable Products of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Industrial Supplies n Gate Drive Bias
TYPICAL APPLICATION Efficiency
90 1000
5V Step-Down Converter
VIN = 12V VIN 80 100 5.6V TO 42V C3 POWER LOSS (mW) 0.47µF VIN BOOST L1 70 10 LT3973 15µH VOUT OFF ON EN/UVLO SW 5V PG 750mA BD 60 1 EFFICIENCY (%) OUT 15pF 1M C1 RT C2 4.7µF FB 22µF 50 0.1 GND 215k 316k f = 600kHz 40 0.01 3973 TA01a 0.01 0.1 1 10 100 LOAD CURRENT (mA) 3973 TA01b 3973fb For more information www.linear.com/LT3973 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 Typical Application Related Parts
FEATURES DESCRIPTION
n
Ultralow Quiescent Current
The LT®3973 is an adjustable frequency monolithic buck n
2.5µA IQ at 12VIN to 3.3VOUT
switching regulator that accepts a wide input voltage range n
Low Ripple Burst Mode
®
Operation
up to 42V, and consumes only 2.5µA of quiescent current. n
Output Ripple < 10mVP-P
A high efficiency switch is included on the die along with n
Wide Input Voltage Range: 4.2V to 42V Operating
the catch diode, boost diode, and the necessary oscillator, n
Adjustable Switching Frequency: 200kHz to 2.2MHz
control and logic circuitry. Low ripple Burst Mode operation n
Integrated Boost and Catch Diodes
maintains high efficiency at low output currents while keep- n
750mA Output Current
ing the output ripple below 10mV in a typical application. n
Excellent Start-Up and Dropout Performance
A minimum dropout voltage of 530mV is maintained when n
Fixed Output Voltages: 3.3V, 5V
the input voltage drops below the programmed output volt- n
1.9µA I
age, such as during automotive cold crank. Current mode
Q at 12VIN
n topology is used for fast transient response and good loop Accurate Programmable Undervoltage Lockout n stability. A catch diode current limit provides protection Low Shutdown Current: IQ = 0.75µA n against shorted outputs and overvoltage conditions, with Internal Catch Diode Current Limit n thermal shutdown providing additional fault protection. An Power Good Flag n accurate programmable undervoltage lockout feature is Thermal Shutdown n available, producing a low shutdown current of 0.75µA. Small, Thermally Enhanced 10-Lead MSOP and A power good flag signals when VOUT reaches 90% of (3mm × 3mm) DFN Packages the programmed output voltage. The LT3973 is available
APPLICATIONS
in small, thermally enhanced 10-lead MSOP and 3mm × 3mm DFN packages. n Automotive Battery Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Power for Portable Products of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Industrial Supplies n Gate Drive Bias
TYPICAL APPLICATION Efficiency
90 1000
5V Step-Down Converter
VIN = 12V VIN 80 100 5.6V TO 42V C3 POWER LOSS (mW) 0.47µF VIN BOOST L1 70 10 LT3973 15µH VOUT OFF ON EN/UVLO SW 5V PG 750mA BD 60 1 EFFICIENCY (%) OUT 15pF 1M C1 RT C2 4.7µF FB 22µF 50 0.1 GND 215k 316k f = 600kHz 40 0.01 3973 TA01a 0.01 0.1 1 10 100 LOAD CURRENT (mA) 3973 TA01b 3973fb For more information www.linear.com/LT3973 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 Typical Application Related Parts
