LT8697 - USB 5V 2.5A Output, 42V Input Synchronous Buck with Cable Drop Compensation

Features

  • Wide Input Range: 5V to 42V
  • Low Dropout Under All Conditions: 450mV at 2.1A
  • Accurate 5V Output: ±1.3% Over Full Temperature Range
  • Programmable Cable Drop Compensation
  • Programmable Output Current Limit
  • Output Current Monitor
  • Dual Input Feedback Permits Regulation on Output of USB Switch
  • Forced Continuous Mode for Fast Load Step Response
  • High Efficiency Synchronous Operation at 2MHz:
    93% Efficiency at 2.1A, 5VOUT from 12VIN
    95% Efficiency at 0.9A, 5VOUT from 12VIN
  • Fast Minimum Switch-On Time: 45ns
  • Adjustable Output from 5.0V to 5.25V
  • Adjustable and Synchronizable: 300kHz to 2.2MHz
  • Small Thermally Enhanced 3mm × 5mm 24-Lead QFN Package

Typical Application

LT8697 Typical Application
LT8697 Typical Application

Description

The LT®8697 is a compact, high efficiency, high speed synchronous monolithic 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. Forced continuous operation allows the LT8697 to sink current, further enhancing accurate 5V regulation during load transients.

Accurate and programmable output current limit, a power good indicator pin and an output current monitor pin improve system reliability and safety, allow the user to implement latch-off or auto-retry functionality and can eliminate the need for a USB switch IC. Dual feedback allows regulation on the output of a USB switch and limits cable drop compensation to a maximum of 5.8V output, protecting USB devices during fault conditions. Thermal shutdown provides additional protection by limiting power dissipation in the IC during an overtemperature fault.

The LT8697 is available in a small 24-lead 3mm × 5mm package with an exposed pad for low thermal resistance.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LT8697EUDD#PBF 3x5 QFN-24 UDD E 05-08-1833 Yes
LT8697EUDD#TRPBF 3x5 QFN-24 UDD E 05-08-1833 Yes
LT8697HUDD#PBF 3x5 QFN-24 UDD H 05-08-1833 Yes
LT8697HUDD#TRPBF 3x5 QFN-24 UDD H 05-08-1833 Yes
LT8697IUDD#PBF 3x5 QFN-24 UDD I 05-08-1833 Yes
LT8697IUDD#TRPBF 3x5 QFN-24 UDD I 05-08-1833 Yes


LT8697 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • 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 Temp Price
(1-99)
Price
(1k)*
RoHS
LT8697EUDD#PBF 3x5 QFN-24 E $5.07 $3.55 Yes
LT8697EUDD#TRPBF 3x5 QFN-24 E $3.61 Yes
LT8697HUDD#PBF 3x5 QFN-24 H $5.94 $4.16 Yes
LT8697HUDD#TRPBF 3x5 QFN-24 H $4.22 Yes
LT8697IUDD#PBF 3x5 QFN-24 I $5.59 $3.91 Yes
LT8697IUDD#TRPBF 3x5 QFN-24 I $3.97 Yes
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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.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1973A LT8697 Demo Board | 6V ≤ VIN ≤ 42V, 5V @ 2.5A USB Supply Output, Cable Drop Compensation $125.00
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Click here to view our complete list of demo boards

Applications

  • Automotive and Industrial USB
  • Precision 5V Supply

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, 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

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LT8697

Technical Support