LT3686A 37V/1.2A Step-Down Regulator in 3mm 3mm DFN and MSE Fe A Description Wide Input Range: The LT 3686A is a current mode PWM step-down DC/DC Operation from 3.6V to 37V converter with an internal power switch. The wide input Overvoltage Lockout Protects Circuit Through range of 3.6V to 37V makes the LT3686A suitable for 60V Transients regulating power from a wide variety of sources, including Low Minimum On-Time: 24V industrial supplies and automotive batteries. Its high Converts 16V to 3.3V at 2MHz maximum frequency allows the use of tiny inductors and IN OUT 1.2A Output Current capacitors, resulting in a very small solution. Operating Adjustable Frequency: 300kHz to 2.5MHz frequency above the AM band avoids interfering with radio Constant Switching Frequency at Light Loads reception, making the LT3686A particularly suitable for Can Be Synchronized to External Clock automotive applications. Tracking and Soft-Start Cycle-by-cycle current limit, thermal shutdown and DA Precision UVLO current sense provide protection against fault conditions. Short-Circuit Robust Soft-start and frequency foldback eliminate input current I in Shutdown <1A Q surge during start-up. An optional internal regulated active Internally Compensated load at the output via the BD pin keeps the LT3686A at Thermally Enhanced MSOP and 3mm 3mm DFN full switching frequency at light loads, resulting in low, Packages predictable output ripple above the audio and AM bands. Internal compensation and an internal boost diode reduce Applic A external component count. Automotive Systems The LT3686A offers external synchronization capability, Battery-Powered Equipment whereas the LT3686 does not. Wall Transformer Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective Distributed Supply Regulation owners. t Al Applic A 3.3V Step-Down Converter 12V Efficiency (2MHz) IN 90 V IN V BD IN 80 6V TO 37V 3.3V OUT 2.2F EN/UVLO BOOST 0.22F 70 5V OUT 2MHz LT3686A 6.8H 60 SW V SYNC/MODE OUT 3.3V 50 MBRM140 1.2A SS 40 DA 31.6k 10nF RT 30 FB GND 20 10k 22F 31.6k 10 3686A TA01a 0 0 200 400 600 800 1000 1200 (V 6V TO 16V AT 2MHz) IN LOAD CURRENT (mA) 3686A TA01b 3686afa 1 EFFICIENCY (%) tion ypic tions turesLT3686A Absolute M A Mu M rA Gs (Note 1) SYNC/MODE Voltage ...................................................6V Input Voltage (V ) (Note 7) ......................................60V IN Operating Junction Temperature Range (Note 2) BOOST Voltage .........................................................55V LT3686AE ........................................... 40C to 125C BOOST Pin Above SW Pin .........................................25V LT3686AI............................................ 40C to 125C FB Voltage ...................................................................6V LT3686AH .......................................... 40C to 150C EN/UVLO Voltage (Note 7) ........................................60V Storage Temperature Range ................... 65C to 150C BD Voltage ................................................................25V Lead Temperature (MSE Package Only, RT Voltage...................................................................6V Soldering, 10 Sec) ................................................ 300C SS Voltage ...............................................................2.5V p Fi G A TOP VIEW TOP VIEW GND 1 12 SW V 1 10 SW IN V 2 11 SW IN BD 2 9 DA BD 3 10 DA 13 11 FB 3 8 BOOST FB 4 GND 9 BOOST GND SS 5 8 SYNC/MODE SS 4 7 SYNC/MODE RT 6 7 EN/UVLO RT 5 6 EN/UVLO MSE PACKAGE DD PACKAGE 12-LEAD PLASTIC MSOP 10-LEAD (3mm 3mm) PLASTIC DFN = 40C/W, = 10C/W JA JC EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB = 43C/W JA EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB Der in F MA LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3686AEDD PBF LT3686AEDD TRPBF LFRK 10-Lead Plastic DFN 40C to 125C LT3686AIDD PBF LT3686AIDD TRPBF LFRK 10-Lead Plastic DFN 40C to 125C LT3686AEMSE PBF LT3686AEMSE TRPBF 3686A 12-Lead Plastic MSOP 40C to 125C LT3686AIMSE PBF LT3686AIMSE TRPBF 3686A 12-Lead Plastic MSOP 40C to 125C LT3686AHMSE PBF LT3686AHMSE TRPBF 3686A 12-Lead Plastic MSOP 40C to 150C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. *For more information on lead free part marking, go to: