CURRENT (A) LT8697 USB 5V 2.5A Output, 42V Input Synchronous Buck with Cable Drop Compensation FEATURES DESCRIPTION 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, 5V from 12V OUT IN eliminate the need for a USB switch IC. Dual feedback al- 95% Efficiency at 0.9A, 5V from 12V OUT IN 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, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Automotive and Industrial USB of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Precision 5V Supply TYPICAL APPLICATION 2MHz 5V Step-Down Converter with Cable Drop Compensation Transient Response Through 3 Meters AWG 20 Twisted-Pair Cable V IN 5.50 5 6V TO 42V 0.1F 3 METERS AWG 20 V TWISTED PAIR CABLE OUT 4.7F V BST IN 5.25 4 3.3H 0.018 0.1 V OUT EN/UV SW PG SYS 5.00 3 LT8697 47F 1nF V LOAD INTV CC 2 10k + 1F ICTRL ISP 4.75 2 V LOAD SYNC ISN I LOAD 5V, 2.4A 50mA/s TR/SS USB5V 4.50 1 10nF RT RCBL 16.5k GND PGND 18.2k 4.25 0 0.1 100s/DIV 8697 TA01b 8697 TA01a 8697fb 1 For more information www.linear.com/LT8697 LOAD VOLTAGE (V)LT8697 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV, PG, ISP, ISN ...........................................42V IN SYS ...........................................................................30V USB5V .....................................................................3mA 24 23 22 21 1 SYNC 20 USB5V BST Above SW ............................................................4V TR/SS 2 19 PG TR/SS, ICTRL..............................................................4V RT 3 SYS 18 RT, RCBL .....................................................................2V EN/UV 4 INTV 17 CC 25 SYNC ..........................................................................6V 5 V 16 BST IN GND Operating Junction Temperature Range (Notes 2, 3) 6 V 15 SW IN LT8697E ............................................ 40C to 125C PGND 7 14 SW LT8697I ............................................. 40C to 125C PGND 8 SW 13 9 10 11 12 LT8697H ............................................ 40C to 150C Storage Temperature Range .................. 65C to 150C UDD PACKAGE 24-LEAD (3mm 5mm) PLASTIC QFN = 46C/W, = 5C/W JA JC EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8697EUDD PBF LT8697EUDD TRPBF LGGW 24-Lead (3mm 5mm) Plastic QFN 40C to 125C LT8697IUDD PBF LT8697IUDD TRPBF LGGW 24-Lead (3mm 5mm) Plastic QFN 40C to 125C LT8697HUDD PBF LT8697HUDD TRPBF LGGW 40C to 150C 24-Lead (3mm 5mm) Plastic QFN Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: