Features and Benefits
- Accurate 5V Output
- Programmable Cable Drop Compensation
- Programmable Output Current Limit
- Adjustable Output from 5.0V to 6.1V
- Dual Input Feedback Permits Regulation on Output of USB Switch
- Active Load Reduces Output Overshoot
- FLT Flag Indicates Overcurrent on the USB Output
- 1.5ms FLT Flag Delay Filters Hot Plug Events
- USB Output Current Monitor
- Wide Input Rage: Operation from 5V to 35V
- Withstands Input Transient to 60V
- 2.5A Maximum Output Current
- Survives Output Short to GND and Car Battery
- Adjustable Switching Frequency: 300kHz to 2.2MHz
- Synchronizable from 300kHz to 2.2MHz
- Small, Thermally Enhanced 16-Lead MSOP Package
The LT3697 is a 35V, 2.5A step-down switching regulator designed to power 5V USB applications. A precise output voltage and programmable cable drop compensation maintain accurate 5V regulation at the USB socket connected to the end of a long cable. The accurate, programmable current limit can eliminate the need for a USB power switch and improve system reliability. The provided 180mA active load reduces output overshoot during load transients. Dual feedback allows regulation on the output of a USB switch and limits cable drop compensation to a maximum of 6.1V output, protecting USB devices during fault conditions. A separate 5V output can be taken from the SYS terminal to power auxiliary circuitry such as a USB hub controller. The LT3697 also provides a load current monitor output and an overcurrent fault indicator.
The LT3697 operates from 300kHz to 2.2MHz and withstands input voltage transients up to 60V. The device's output survives shorts to ground and to the battery. A current mode topology is used for fast transient response and good loop stability. Shutdown reduces input supply current to less than 1μA. The LT3697 is available in a 16-lead MSOP package with an exposed pad for low thermal resistance.
- Automotive USB
- Industrial USB
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 1893A is a USB 5V, 2.4A output, 35V input buck with cable drop compensation featuring the LT3697. The LT3697 is a step-down switching regulator designed to power 5V USB applications. A precise output voltage and programmable cable drop compensation maintain accurate 5V regulation at the USB socket at the end of a long cable. The circuit was designed to run at 500kHz to avoid the AM band. The demo board has an EMI filter installed. The radiated EMI performance of the board is on Figures 3 to 5, showing the circuit passes CISPR25 Class 5 with a wide margin.
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:
LT3697 Companion Parts
Recommended Related 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.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.