LT3682 - 1A Micropower Step-Down Switching Regulator

Features

• Click Here for LT3682 Evaluation Kit
• Wide Input Range:
  Operation from 3.6V to 36V
  Overvoltage Lockout Protects Circuits through
  60V Transients
• 1A Output Current
• Low Ripple Burst Mode® Operation
  I_Q = 75μA at 12V_IN to 3.3V_OUT
  Output Ripple < 15mV_P-P
• Adjustable Switching Frequency: 250kHz to 2.2MHz
• Short-Circuit Protected
• Synchronizable Between 300kHz and 2.2MHz
• 0.8V Feedback Reference Voltage
• Output Voltage 0.8V to 20V
• Soft-Start Capability
• Power Good Flag
• Small 12-Pin Thermally Enhanced 3mm × 3mm DFN Package

Typical Application

Description

The LT3682 is an adjustable frequency (250kHz to 2.2MHz) monolithic buck switching regulator that accepts input voltages up to 36V. A high efficiency 0.5Ω switch is included on the device along with a boost diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. A SYNC pin allows the user to synchronize the part to an external clock, and to choose between Low Ripple Burst Mode operation and standard PWM operation.

The Low Ripple Burst Mode maintains high efficiency at low output currents while keeping output ripple below 15mV in typical applications. 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. Protection circuitry senses the current in the power switch and external Schottky catch diode to protect the LT3682 against short-circuit conditions. Frequency foldback and thermal shutdown provide additional protection.

The LT3682 is available in a 12-Pin 3mm × 3mm DFN with exposed pad for low thermal resistance.

Packaging

DFN-12

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
LT3682EDD#PBF	DFN	12	E	$4.22	$2.95	View
LT3682EDD#TRPBF	DFN	12	E		$3.01	View
LT3682IDD#PBF	DFN	12	I	$4.64	$3.25	View
LT3682IDD#TRPBF	DFN	12	I		$3.31	View
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Request Samples

^* 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.

Evaluation Kits

Part Number	Description	Price
DC1222A	LT3682EDD Demo Board | 1A Micropower Ste-Down Switching Regulator	$125.00
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Applications

• Automotive Battery Regulation
• Automotive Entertainment Systems
• Industrial Supplies
• Power for Portable Products
• Distributed Supply Regulation

Simulate

LTSpice IV 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 IV, 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 LT3682.
  
  
• Step 3. If LTspice IV 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 demonstration circuit by selecting "Open" from the "File" menu.

For our complete list of hundreds of ready to run demo circuits, visit our LTspice IV Demo Circuits Collection