LTC7862 140V High Efficiency Switching Surge Stopper FEATURES DESCRIPTION n V Clamp Stops High Voltage Input Surges The LTC 7862 high efficiency switching surge stopper pro- OUT n 100% Duty Cycle Pass-Through Mode During tects loads from high voltage transients. High efficiency Normal Operation switching allows high output currents, small solution sizes, n Switches During Overvoltage or Overcurrent and high reliability. During an input overvoltage event, the Transients and Faults and During Startup LTC7862 controls the gates of two external N-channel n High Efficiency Switching Enables Long Duration MOSFETs to act as a switching DC/DC step-down regu- Surge Protection and High Output Currents lator. This maintains the output voltage at a safe value, n Wide V Range: 4V to 140V (150V Abs Max) allowing the loads to continue to operate through the input IN n Adjustable Output Voltage Clamp Up to 60V overvoltage event. During normal operation, the LTC7862 n Adjustable Output Overcurrent Protection turns on the top external N-channel MOSFET continuously, n R or Inductor DCR Current Sensing passing the input voltage through to the output, with mini- SENSE n Power Inductor Reduces Input EMI in Normal Mode mal voltage drop. Using a fast peak current comparator, n Adjustable Soft-Start for Inrush Current Limiting the LTC7862 also limits the maximum output current to n Programmable Fault Timer protect against overcurrent and short-circuit faults. n Open-Drain Fault Warning Indicator An adjustable timer limits the time that the LTC7862 can n 2.7% Retry Duty Cycle During Faults spend switching during an overvoltage, overcurrent, or n Adjustable Switching Frequency: 50kHz to 900kHz startup condition. When the timer expires, the external n Adjustable Input Voltage Turn-On Threshold MOSFETs are turned off for a cooldown period and then n Adjustable Input Overvoltage Lockout Threshold the LTC7862 restarts. By strictly limiting how long the n 20-Pin 4mm 5mm QFN and TSSOP Packages LTC7862 can switch, when the power loss is relatively high, the components and thermal design can be opti- APPLICATIONS mized for normal pass-through operation while still safely n Automotive/Avionic/Industrial Surge Protection operating through high voltage input surges and/or over- n Automotive Load Dump Protection current events. n Vehicle Power Including ISO7637 All registered trademarks and trademarks are the property of their respective owners. n Military Power Including MIL1275 TYPICAL APPLICATION 28V, 20A with 100V Overvoltage Protection L, 6.8H *V MTOP 2 OUT Overvoltage Protector Regulates V IN CLAMPED AT 34V 8V TO 100V C INB 20A Output at 28V During V Transient C INA IN 2.05k 2.2F MBOT 0.47F D1 C 22F 2.21k OUTB C 3 OUTA 6.8F 1M DRV CC 100F 3 2.2F 100V INPUT SURGE V IN + 1M 34V RUN V TG BG SW BOOST SENSE SENSE IN 28V V /V IN OUT DRV CC V 50V/DIV FB V INTV OUT CC 24.3k 4.7F 0.1F DRVUV 36.5k SW FREQ 100V/DIV LTC7862 TMR ITH INTV CC WARNB 22F 5V/DIV 4.75k SS 100k 0.1F 100pF 6.8nF OVLO 7862 TA01b EXTV WARNB WARNB 100ms/DIV CC GND 7862 TA01a MTOP/MBOT: INFINEON BSC035N10NS5 C : SUN 63CE100LX * V FOLLOWS V WHEN V < 34V OUTA OUT IN IN L: COILCRAFT SER2918H-682KL C : TDK C4532X7R1H685K250KB V CLAMPS AT 34V WHEN V > 34V OUTB OUT IN C : SUNCON 160CE22LH D1: NEXPERIA: PNE20010ER INA C : TDK C4532X7R2A225K230KA INB Rev 0 1 Document Feedback For more information www.analog.comLTC7862 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Supply Voltage (V ) ....................... 0.3V to 150V TMR, WARNB Voltages ................................ 0.3V to 6V IN Top Side Driver Voltage BOOST ............... 0.3V to 150V EXTV Voltage ......................................... 0.3V to 14V CC Switch Voltage (SW) ................................... 5V to 150V ITH, V Voltages ......................................... 0.3V to 6V FB DRV , (BOOST-SW) Voltages ....................0.3V to 11V SS, OVLO Voltages ...................................... 0.3V to 6V CC BG, TG ............................................................... (Note 8) Operating Junction Temperature Range (Notes 2, 3) RUN Voltage............................................. 0.3V to 150V LTC7862E, LTC7862I ......................... 40C to 125C + SENSE , SENSE Voltages ......................... 0.3V to 65V LTC7862H .......................................... 40C to 150C FREQ, DRVUV Voltages ............................... 0.3V to 6V Storage Temperature Range .................. 65C to 150C PIN CONFIGURATION TOP VIEW TOP VIEW + 1 SENSE 20 OVLO 2 SENSE 19 INTV CC 20 19 18 17 3 SS 18 DRVUV SS 1 16 DRVUV 4 V 17 RUN FB V 2 15 RUN FB 5 ITH 16 EXTV CC ITH 3 14 EXTV CC 21 21 6 TMR 15 V 4 13 V IN TMR IN 7 FREQ 14 DRV FREQ 5 12 DRV CC CC 8 WARNB 6 11 GND WARNB 13 GND 9 TG 12 BG 7 8 9 10 10 SW 11 BOOST FE PACKAGE 20-LEAD PLASTIC TSSOP UFD PACKAGE 20-LEAD (4mm 5mm) PLASTIC QFN T = 150C, = 38C/W, = 10C/W JMAX JA JC EXPOSED PAD (PIN 21) IS GND, MUST BE T = 150C, = 43C/W, = 3.4C/W JMAX JA JC SOLDERED TO PCB FOR RATED ELECTRICAL AND EXPOSED PAD (PIN 21) IS GND, MUST BE THERMAL CHARACTERISTICS SOLDERED TO PCB FOR RATED ELECTRICAL AND THERMAL CHARACTERISTICS ORDER INFORMATION