LT3991IDD#TRPBF

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Analog Devices Inc./Maxim Integrated

CONV DC-DC 4.3V TO 55V SYNCHRONOUS STEP DOWN SINGLE-OUT 1.19V TO 30V 1.2A 10-PIN DFN EP T/R

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LT3991IDD#TRPBF

Active

Analog Devices Inc./Maxim Integrated

CONV DC-DC 4.3V TO 55V SYNCHRONOUS STEP DOWN SINGLE-OUT 1.19V TO 30V 1.2A 10-PIN DFN EP T/R

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Description Specifications Series Pricing CAD Documents

Description

General part information

LT3991 Series

The LT3991 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 55V. Low quiescent current design consumes only 2.8μA of supply current while regulating with no load. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 15mV in a typical application. An internally compensated current mode topology is used for fast transient response and good loop stability. A high efficiency 0.44Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control and logic circuitry. An accurate 1V threshold enable pin can be used to shut down the LT3991, reducing the input supply current to 700nA. A capacitor on the SS pin provides a controlled inrush current (soft-start). A power good flag signals when VOUTreaches 91% of the programmed output voltage. The LT3991 is available in small 10-pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.ApplicationsAutomotive Battery RegulationPower for Portable ProductsIndustrial Supplies

Technical Specifications

Parameters and characteristics for this part

Specification	LT3991IDD#TRPBF

Current - Output	1.2 A
Frequency - Switching (Max)	2 MHz
Frequency - Switching (Min)	200 kHz
Function	Step-Down
Mounting Type	Surface Mount
Number of Outputs	1
Operating Temperature (Max)	125 °C
Operating Temperature (Min)	-40 °C
Output Configuration	Positive
Output Type	Adjustable
Package / Case	10-WFDFN Exposed Pad
Package Length	3 mm
Package Name	10-DFN
Package Width	3 mm
Synchronous Rectifier	No
Topology	Buck
Voltage - Input (Max)	55 V
Voltage - Input (Min)	4.3 V
Voltage - Output (Max)	30 V
Voltage - Output (Min/Fixed)	1.19 V

LT3991 Series

55V, 1.2A Step-Down Regulator with 2.8μA Quiescent Current

Part	Function	Package Name	Number of Outputs	Voltage - Output (Max)	Voltage - Input (Min)	Mounting Type	Topology	Output Type	Voltage - Input (Max)	Current - Output	Output Configuration	Package Width	Package Features	Package Length	Operating Temperature (Max)	Operating Temperature (Min)	Frequency - Switching (Max)	Frequency - Switching (Min)	Synchronous Rectifier	Voltage - Output (Min/Fixed)	Package / Case
Analog Devices Inc./Maxim Integrated LT3991IMSE#TRPBF	Step-Down	10-MSOP 10-MSOP-EP	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm	Exposed Pad	0.118 in	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V
Analog Devices Inc./Maxim Integrated LT3991IDD#PBF	Step-Down	10-DFN	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm		3 mm	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V	10-WFDFN Exposed Pad
Analog Devices Inc./Maxim Integrated LT3991IMSE#PBF	Step-Down	10-MSOP 10-MSOP-EP	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm	Exposed Pad	0.118 in	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V
Analog Devices Inc./Maxim Integrated LT3991EMSE-5#TRPBF	Step-Down	10-MSOP 10-MSOP-EP	1		4.3 V	Surface Mount	Buck	Fixed	55 V	1.2 A	Positive	3 mm	Exposed Pad	0.118 in	125 °C	-40 °C	2 MHz	200 kHz	No	5 V
Analog Devices Inc./Maxim Integrated LT3991EMSE#TRPBF	Step-Down	10-MSOP 10-MSOP-EP	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm	Exposed Pad	0.118 in	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V
Analog Devices Inc./Maxim Integrated LT3991IDD#TRPBF	Step-Down	10-DFN	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm		3 mm	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V	10-WFDFN Exposed Pad
Analog Devices Inc./Maxim Integrated LT3991EMSE-5#PBF	Step-Down	10-MSOP 10-MSOP-EP	1		4.3 V	Surface Mount	Buck	Fixed	55 V	1.2 A	Positive	3 mm	Exposed Pad	0.118 in	125 °C	-40 °C	2 MHz	200 kHz	No	5 V
Analog Devices Inc./Maxim Integrated LT3991IMSE-5#PBF	Step-Down	10-MSOP 10-MSOP-EP	1		4.3 V	Surface Mount	Buck	Fixed	55 V	1.2 A	Positive	3 mm	Exposed Pad	0.118 in	125 °C	-40 °C	2 MHz	200 kHz	No	5 V
Analog Devices Inc./Maxim Integrated LT3991IDD	Step-Down	10-DFN	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm		3 mm	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V	10-WFDFN Exposed Pad
Analog Devices Inc./Maxim Integrated LT3991EDD#TRPBF	Step-Down	10-DFN	1	30 V	4.3 V	Surface Mount	Buck	Adjustable	55 V	1.2 A	Positive	3 mm		3 mm	125 °C	-40 °C	2 MHz	200 kHz	No	1.19 V	10-WFDFN Exposed Pad

Pricing

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CAD

3D models and CAD resources for this part

Documents

Technical documentation and resources

LT3991IDD#TRPBF | Datasheet

Tape and Reel Packaging

R530 Reliability Data