LTC7862 140V High Efficiency Switching Surge Stopper FEATURESDESCRIPTION n VOUT Clamp Stops High Voltage Input Surges The LTC®7862 high efficiency switching surge stopper pro- 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 VIN Range: 4V to 140V (150V Abs Max) allowing the loads to continue to operate through the input 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 RSENSE or Inductor DCR Current Sensing passing the input voltage through to the output, with mini- 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 APPLICATION28V, 20A with 100V Overvoltage Protection MTOP ×2 L, 6.8µH V *VOUT IN Overvoltage Protector Regulates 8V TO 100V CLAMPED AT 34V CINB C 20A INA Output at 28V During V 2.2µF MBOT 0.47µF 2.05k IN Transient 22µF D1 2.21k C ×3 OUTB COUTA 1M DRV 6.8µF CC 100µF 2.2µF ×3 100V INPUT SURGE VIN 1M RUN VIN TG BG SW BOOST SENSE+ SENSE– V 28V 34V IN/VOUT DRVCC VFB 50V/DIV INTV V CC OUT 24.3k 4.7µF 0.1µF 36.5k DRVUV SW FREQ 100V/DIV LTC7862 ITH TMR INTVCC WARNB 22µF 4.75k SS 5V/DIV 100pF 6.8nF 0.1µF 100k OVLO EXTV 7862 TA01b CC WARNB WARNB 100ms/DIV GND 7862 TA01a MTOP/MBOT: INFINEON BSC035N10NS5 COUTA: SUN 63CE100LX * VOUT FOLLOWS VIN WHEN VIN < 34V L: COILCRAFT SER2918H-682KL COUTB: TDK C4532X7R1H685K250KB VOUT CLAMPS AT 34V WHEN VIN > 34V CINA: SUNCON 160CE22LH D1: NEXPERIA: PNE20010ER CINB: TDK C4532X7R2A225K230KA Rev 0 Document Feedback For more information www.analog.com 1 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS TIMING DIAGRAM FUNCTIONAL DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION TYPICAL APPLICATION RELATED PARTS
