LT8495 SEPIC/Boost Converter with 2A, 70V Switch, 9A Quiescent Current, POR and Watchdog Timer FEATURES DESCRIPTION n Wide Input Voltage Range of ~1V to 60V The LT 8495 is an adjustable frequency (250kHz to 1.5MHz) (2.5V to 32V for Start-Up) monolithic switching regulator with a power-on reset and n Low Ripple Burst Mode Operation watchdog timer. Quiescent current can be less than 9A n 9A I at 12V to 5.0V Q IN OUT when operating and is ~0.3A when SWEN, WDE and RSTIN n Output Ripple (<10mV Typ.) are low. Configurable as a SEPIC, boost or flyback con- n Dual Supply Pins: verter, the low ripple Burst Mode operation maintains high n Improves Efficiency efficiency at low output current while keeping output n Reduces Minimum Supply Voltage to ~1V after ripple below 10mV. Dual supply pins (V and BIAS) allow IN Start-Up to Extend Battery Life the part to automatically operate from the most efficient n Integrated 2A/70V Power Switch supply. Input supply voltage can be up to 60V for SEPIC n Programmable Watchdog Timer Can Operate When topologies and up to 32V (with ride-through up to 60V) V Supply Is Removed IN for boost and flyback topologies. After start-up, battery n Programmable Power-On Reset Timer (POR) with life is extended since the part can draw current from its RST Functional for Input Supply Down to 1.3V output (BIAS) even when V voltage drops below 2.5V. IN n FMEA Fault Tolerant in TSSOP Package The reset and watchdog timeout periods are independently n Fixed Frequency PWM, SEPIC/BOOST/FLYBACK adjustable using external capacitors. Using a resistor divider Topologies on the SWEN pin provides a programmable undervoltage n Programmable Switching Frequency: lockout (UVLO) for the converter. A resistor divider connected 250kHz to 1.5MHz to RSTIN provides UVLO control that asserts the RST pin. n UVLO Programmable on SWEN and RSTIN Pins n Soft-Start Programmable with One Capacitor Additional features such as frequency foldback and soft- n Small 20-Lead QFN or 20-Lead TSSOP Packages start are integrated. Fault tolerance in the TSSOP allows for adjacent pin shorts or an open without raising the APPLICATIONS output voltage above its programmed value. The LT8495 is available in 20-lead QFN and 20-lead TSSOP packages n Automotive ECU Power with exposed pads for low thermal resistance. n Power for Portable Products L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Industrial Supplies of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION No-Load Supply Current Efficiency 450kHz, 5V Output SEPIC Converter 25 90 2.2F 15H V OUT V IN 5V 85 V = 24V 3V TO 60V IN 20 0.35A (V = 3V) IN 47F 2.2F 0.6A (V = 5V) 15H 1M IN 2 4.7pF 80 1.0A (V >12V) V = 12V IN IN 15 V = 5V 75 IN 8.87k SW BIAS 10 V RSTIN IN 70 SWEN FB WATCHDOG ENABLED LT8495 316k CWDT 5 65 GND 1nF CPOR WATCHDOG DISABLED SS 4.7nF WDO 1F RT WDE 0 60 C 0 12 24 36 48 60 0.0 0.2 0.4 0.6 0.8 1.0 169k RST WDI INPUT VOLTAGE (V) LOAD CURRENT (A) 8495 TA01a 8495 TA01b 8495 TA01c 8495fa 1 For more information www.linear.com/LT8495 SUPPLY CURRENT (A) EFFICIENCY (%)LT8495 ABSOLUTE MAXIMUM RATINGS (Note 1) V , BIAS Voltage ......................................................60V CPOR, CWDT, SS Voltage ...........................................3V IN SWEN, WDE, RSTIN Voltage .....................................60V Operating Junction Temperature Range FB Voltage .................................................................60V LT8495E, LT8495I (Notes 2, 3) .......... 40C to 125C SW Voltage ...............................................................70V LT8495H (Notes 2, 3) ........................ 40C to 150C WDI, RST, WDO Voltage ..............................................6V Storage Temperature Range .................. 65C to 150C RT Voltage ..................................................................6V Lead Temperature (Soldering, 10 sec) FE Package .......................................................300C PIN CONFIGURATION TOP VIEW TOP VIEW BIAS 1 20 SW FB 2 20 19 18 17 16 19 NC FB 3 18 V IN SS 1 GND 15 NC 4 17 NC GND RT 2 14 CPOR 5 16 WDI 21 21 GND 3 13 GND GND GND CWDT 6 15 WDO GND 4 12 SW RST 7 14 GND RSTIN 5 11 GND SS 8 13 WDE NC 9 6 7 8 9 10 12 SWEN RT 10 11 RSTIN FE PACKAGE UF PACKAGE 20-LEAD PLASTIC TSSOP 20-LEAD (4mm 4mm) PLASTIC QFN = 38C/W JA = 47C/W JA EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8495EUF PBF LT8495EUF TRPBF 8495 20-Lead (4mm 4mm) Plastic QFN 40C to 125C LT8495IUF PBF LT8495IUF TRPBF 8495 20-Lead (4mm 4mm) Plastic QFN 40C to 125C LT8495EFE PBF LT8495EFE TRPBF LT8495FE 20-Lead Plastic TSSOP 40C to 125C LT8495IFE PBF LT8495IFE TRPBF LT8495FE 20-Lead Plastic TSSOP 40C to 125C LT8495HFE PBF LT8495HFE TRPBF LT8495FE 20-Lead Plastic TSSOP 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. 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