Features and Benefits
- Wide Input Voltage Range: Operation from 4.5V to 45V
- Overvoltage Lockout Provides Protection Up to 60V
- Internal High Side and Low Side Power Switches
- No Compensation Required
- 100mA Output Current
- Low Dropout Operation: 100% Duty Cycle
- Low Quiescent Current: 12μA
- 0.8V ±1% Feedback Voltage Reference
- Adjustable Peak Current Limit
- Internal and External Soft-Start
- Precise RUN Pin Threshold with Adjustable Hysteresis
- 3.3V, 5V and Adjustable Output Versions
- Only Three External Components Required for Fixed Output Versions
- Low Profile (0.75mm) 3mm × 3mm DFN and Thermally-Enhanced MS8E Packages
The LTC3631 is a high voltage, high efficiency step-down DC/DC converter with internal high side and synchronous power switches that draws only 12μA typical DC supply current at no load while maintaining output voltage regulation.
The LTC3631 can supply up to 100mA load current and features a programmable peak current limit that provides a simple method for optimizing efficiency in lower current applications. The LTC3631’s combination of Burst Mode® operation, integrated power switches, low quiescent current, and programmable peak current limit provides high efficiency over a broad range of load currents.
With its wide 4.5V to 45V input range and internal overvoltage monitor capable of protecting the part from 60V surges, the LTC3631 is a robust converter suited for regulating a wide variety of power sources. Additionally, the LTC3631 includes a precise run threshold and a soft-start feature to guarantee that power system start-up is well-controlled in any environment.
The LTC3631 is available in the thermally enhanced 3mm × 3mm DFN and MS8E packages.
- 4mA to 20mA Current Loops
- Industrial Control Supplies
- Distributed Power Systems
- Portable Instruments
- Battery-Operated Devices
- Automotive Power Systems
Markets and Technologies
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit DC1499A is a high efficiency step-down DC/DC converter featuring LTC3631 with internal high side and synchronous power switches that draws only 12μA quiescent current. It has a wide 4.5V to 45V input range and internal over voltage monitor capable of protecting the part through 60V surges. The jumper selectable output is up to 5V. LTC3631 can supply up to 100mA load current with a programmable peak current limit that provides a simple method for optimizing efficiency in lower current applications. With no compensation required, LTC3631 is easily configured with minimal components.
Documentation & Resources
R526 Reliability Data3/26/2018
DC1499A - Demo Manual9/24/2009
Robust DC/DC Step-Down Converter in 3mm × 3mm DFN Resists 60V Input Surges9/1/2009 LT Journal
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, 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.
Models for the following parts are available in LTspice:
LTC3631 Companion Parts
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.
Sample & Buy
See our Ordering FAQs for answers to questions about online orders, payment options and more.
Buy Now Pricing
(**) Displayed Buy Now Price and Price Range is based on small quantity orders.
(*)The 1Ku 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 Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
Please see the latest communication from our CCO regarding lead times.
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.
Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.