LT8494 SEPIC/Boost DC/DC Converter with 2A, 70V Switch, and 7A Quiescent Current FEATURES DESCRIPTION n Low Ripple Burst Mode Operation: The LT 8494 is an adjustable frequency (250kHz to n 7A I at 12V to 5V 1.5MHz) monolithic switching regulator. Quiescent cur- Q IN OUT n Output Ripple (<10mV Typ.) rent can be less than 7A when operating and is ~0.3A n Dual Supply Pins: when SWEN is low. The LT8494 can be configured as n Improves Efficiency either a SEPIC, boost or flyback converter. n Reduces Minimum Supply Voltage to ~1V After The low ripple Burst Mode operation maintains high n Start-Up to Extend Battery Life efficiency at low output current while keeping output rip- n Wide Input Voltage Range of ~1V to 60V (2.5V to ple below 10mV. Dual supply pins (V and BIAS) allow IN 32V for Start-Up) the part to automatically operate from the most efficient n PG Functional for Input Supply Down to 1.3V supply. Input supply voltage can be up to 60V for SEPIC n FMEA Fault Tolerant in TSSOP Package topologies and up to 32V (with ride-through up to 60V) n Fixed Frequency PWM, SEPIC/BOOST/FLYBACK for boost and flyback topologies. After start-up, battery Topologies life is extended since the part can draw current from its n NPN Power Switch: 2A/70V output (BIAS) even when V voltage drops below 2.5V. IN n Programmable Switching Frequency: 250kHz to 1.5MHz n Using a resistor divider on the SWEN pin provides a pro- UVLO Programmable on SWEN Pin n grammable undervoltage lockout (UVLO) for the con- Soft-Start Programmable with One Capacitor n verter. A power good flag signals when V reaches 92% Small 20-Lead QFN or 20-Lead TSSOP Packages OUT of the programmed output voltage. Additional features such as frequency foldback and soft- APPLICATIONS start are integrated. The LT8494 is available in 20-lead n Automotive ECU Power QFN and 20-lead TSSOP packages with exposed pads n Power for Portable Products for low thermal resistance. Fault tolerance in the TSSOP n Industrial Supplies allows for adjacent pin shorts or an open without raising L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of the output voltage above its programmed value. Analog Devices, Inc. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 450kHz, 5V Output SEPIC Converter No-Load Supply Current Efficiency 20 90 2.2F 15H V V IN OUT 3V TO 60V 5V 85 V = 24V IN 0.35A (V = 3V) IN 15 15H 0.6A (V = 5V) IN 80 1.0A (V > 12V) IN V = 12V IN V = 5V 10 75 IN V SW BIAS IN SWEN 1M 4.7pF LT8494 70 PG 4.7F 5 RT FB 47F SS GND 2 65 169k 1F 316k 8494 TA01a 0 60 0 12 24 36 48 60 0.0 0.2 0.4 0.6 0.8 1.0 INPUT VOLTAGE (V) LOAD CURRENT (A) 8494 TA01b 8494 TA01c 8494fa 1 For more information www.linear.com/LT8494 SUPPLY CURRENT (A) EFFICIENCY (%)LT8494 ABSOLUTE MAXIMUM RATINGS (Note 1) V , BIAS Voltage ......................................................60V Operating Junction Temperature Range IN SWEN Voltage ...........................................................60V LT8494E, LT8494I (Notes 2, 3) .......... 40C to 125C FB Voltage .................................................................60V LT8494H (Notes 2, 3) ........................ 40C to 150C SW Voltage ...............................................................70V Storage Temperature Range .............. 65C to 150C PG Voltage ..................................................................6V Lead Temperature (Soldering, 10 sec) RT Voltage ..................................................................6V FE Package .......................................................300C SS Voltage ..................................................................3V PIN CONFIGURATION TOP VIEW TOP VIEW BIAS 1 20 SW 20 19 18 17 16 FB 2 19 NC FB 3 18 V IN SS GND 1 15 NC 4 17 NC RT 2 14 GND NC 5 16 GND 21 21 GND 3 13 GND GND GND NC 6 15 NC GND 4 12 SW PG 7 14 GND NC 11 GND 5 SS 8 13 NC 6 7 8 9 10 NC 9 12 SWEN RT 10 11 NC FE PACKAGE UF PACKAGE 20-LEAD PLASTIC TSSOP 20-LEAD (4mm 4mm) PLASTIC QFN = 38C/W = 47C/W JA JA EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB