LT3481 - 36V, 2A, 2.8MHz Step-Down Switching Regulator with 50µA Quiescent Current

Features

• Wide Input Range: 3.6V to 34V Operating, 36V Maximum
• 2A Maximum Output Current
• Low Ripple Burst Mode® Operation
   50µA I_Q at 12V_IN to 3.3V_OUT
   Output Ripple < 15mV
• Adjustable Switching Frequency: 300kHz to 2.8MHz
• Low Shutdown Current: I_Q < 1µA
• Integrated Boost Diode
• Power Good Flag
• Saturating Switch Design: 0.18Ω On-Resistance
• 1.265V Feedback Reference Voltage
• Output Voltage: 1.265V to 20V
• Soft-Start Capability
• Synchronizable Between 275kHz to 475kHz
• Small 10-Pin Thermally Enhanced MSOP and (3mm x 3mm) DFN Packages

Typical Application

Description

The LT3481 is an adjustable frequency (300kHz to 2.8MHz) monolithic buck switching regulator that accepts input voltages up to 34V (36V maximum). A high efficiency 0.18Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application. In addition, the LT3481 can further enhance low output current efficiency by drawing bias current from the output when V_OUT is above 3V. Shutdown reduces input supply current to less than 1µA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good flag signals when V_OUT reaches 90% of the programmed output voltage. The LT3481 is available in 10-Pin MSOP and 3mm x 3mm DFN packages with exposed pads for low thermal resistance.

Packaging

MS-10, DFN-10

Order Info

• Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
• Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
• Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number	Package	Pins	Temp	Price (1-99)	Price (1k)*	RoHS Data
LT3481EDD	DFN	10	E	$4.64	$3.25	View
LT3481EDD#PBF	DFN	10	E	$4.64	$3.25	View
LT3481EDD#TR	DFN	10	E		$3.31	View
LT3481EDD#TRPBF	DFN	10	E		$3.31	View
LT3481EMSE	MSOP	10	E	$4.64	$3.25	View
LT3481EMSE#PBF	MSOP	10	E	$4.64	$3.25	View
LT3481EMSE#TR	MSOP	10	E		$3.31	View
LT3481EMSE#TRPBF	MSOP	10	E		$3.31	View
LT3481HDD	DFN	10	H	$5.93	$4.15	View
LT3481HDD#PBF	DFN	10	H	$5.93	$4.15	View
LT3481HDD#TR	DFN	10	H		$4.21	View
LT3481HDD#TRPBF	DFN	10	H		$4.21	View
LT3481HMSE	MSOP	10	H	$5.93	$4.15	View
LT3481HMSE#PBF	MSOP	10	H	$5.93	$4.15	View
LT3481HMSE#TR	MSOP	10	H		$4.21	View
LT3481HMSE#TRPBF	MSOP	10	H		$4.21	View
LT3481IDD	DFN	10	I	$5.57	$3.90	View
LT3481IDD#PBF	DFN	10	I	$5.57	$3.90	View
LT3481IDD#TR	DFN	10	I		$3.96	View
LT3481IDD#TRPBF	DFN	10	I		$3.96	View
LT3481IMSE	MSOP	10	I	$5.57	$3.90	View
LT3481IMSE#PBF	MSOP	10	I	$5.57	$3.90	View
LT3481IMSE#TR	MSOP	10	I		$3.96	View
LT3481IMSE#TRPBF	MSOP	10	I		$3.96	View
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^* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Applications

• Automotive Battery Regulation
• Power for Portable Products
• Distributed Supply Regulation
• Industrial Supplies
• Wall Transformer Regulation

Simulate

LTSpice / SwitcherCAD III is a powerful FREE circuit simulator and schematic capture program, providing macro models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models.

• Step 1. If you do not already have a copy of LTSpice, click here to download and install LTSpice / SwitcherCAD III
  
  
• Step 2. Once LTSpice is installed, click here for a ready to run  demonstration circuit of the LT3481.
  
  
• Step 3. If LTspice / SwitcherCAD III does not automatically open after clicking the above link, you can instead run the simulation by right clicking on the link and selecting “Save Target As”. After saving the file to your computer, start LTSpice and open the demonstartion circuit by selecting "Open" from the "File" menu.