LT8697 USB 5V 2.5A Output, 42V Input Synchronous Buck with Cable Drop Compensation FEATURESDESCRIPTION n Wide Input Range: 5V to 42V The LT®8697 is a compact, high efficiency, high speed n Low Dropout Under All Conditions: 450mV at 2.1A synchronous monolithic step-down switching regulator n Accurate 5V Output: ±1.3% Over Full Temperature designed to power 5V USB applications. A precise output Range voltage and programmable cable drop compensation main- n Programmable Cable Drop Compensation tain accurate 5V regulation at the USB socket connected n Programmable Output Current Limit to the end of a long cable. Forced continuous operation n Output Current Monitor allows the LT8697 to sink current, further enhancing ac- n Dual Input Feedback Permits Regulation on Output curate 5V regulation during load transients. of USB Switch Accurate and programmable output current limit, a power n Forced Continuous Mode for Fast Load Step good indicator pin and an output current monitor pin Response improve system reliability and safety, allow the user to n High Efficiency Synchronous Operation at 2MHz: implement latch-off or auto-retry functionality and can 93% Efficiency at 2.1A, 5VOUT from 12VIN eliminate the need for a USB switch IC. Dual feedback al- 95% Efficiency at 0.9A, 5VOUT from 12VIN lows regulation on the output of a USB switch and limits n Fast Minimum Switch-On Time: 45ns cable drop compensation to a maximum of 5.8V output, n Adjustable Output from 5.0V to 5.25V protecting USB devices during fault conditions. Thermal n Adjustable and Synchronizable: 300kHz to 2.2MHz shutdown provides additional protection by limiting power n Small Thermally Enhanced 3mm × 5mm 24-Lead dissipation in the IC during an overtemperature fault. QFN Package The LT8697 is available in a small 24-lead 3mm × 5mm APPLICATIONS package with an exposed pad for low thermal resistance. L n , LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks Automotive and Industrial USB of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Precision 5V Supply TYPICAL APPLICATION2MHz 5V Step-Down Converter with Cable Drop CompensationTransient Response Through 3 MetersAWG 20 Twisted-Pair Cable VIN 6V TO 42V 5.50 5 0.1µF 3 METERS AWG 20 4.7µF V VOUT TWISTED PAIR CABLE IN BST 3.3µH 5.25 4 0.018Ω 0.1Ω V EN/UV SW OUT CURRENT (A) PG SYS LT8697 47µF 5.00 3 1nF INTV V CC ×2 LOAD 10k 1µF + ICTRL ISP VOLTAGE (V) 4.75 2 SYNC ISN VLOAD I LOAD 5V, 2.4A LOAD TR/SS USB5V 50mA/µs 10nF – 4.50 1 RT RCBL 16.5k GND PGND 18.2k 0.1Ω 4.25 0 8697 TA01a 100µs/DIV 8697 TA01b 8697fb For more information www.linear.com/LT8697 1 Document Outline Features Applications Typical Application Absolute Maximum Ratings Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
