LTC3810 100V Current Mode Synchronous Switching Regulator Controller FEATURESDESCRIPTION n High Voltage Operation: Up to 100V The LTC3810 is a synchronous step-down switching n Large 1 Ω Gate Drivers regulator controller that can directly step-down voltages n No Current Sense Resistor Required from up to 100V, making it ideal for telecom and automo- n Dual N-Channel MOSFET Synchronous Drive tive applications. The LTC3810 uses a constant on-time n Extremely Fast Transient Response valley current control architecture to deliver very low duty n ±0.5% 0.8V Voltage Reference cycles with accurate cycle-by-cycle current limit, without n Programmable Output Voltage Tracking/Soft-Start requiring a sense resistor. n Generates 10V Driver Supply from Input Supply A precise internal reference provides 0.5% DC accuracy. A n Synchronizable to External Clock high bandwidth (25MHz) error amplifi er provides very fast n Selectable Pulse Skip Mode Operation line and load transient response. Large 1Ω gate drivers n Power Good Output Voltage Monitor allow the LTC3810 to drive multiple MOSFETs for higher n Adjustable On-Time/Frequency: tON(MIN) < 100ns current applications. The operating frequency is selected n Adjustable Cycle-by-Cycle Current Limit by an external resistor and is compensated for variations n Programmable Undervoltage Lockout in VIN and can also be synchronized to an external clock n Output Overvoltage Protection for switching-noise sensitive applications. A shutdown pin n 28-Pin SSOP Package allows the LTC3810 to be turned off, reducing the supply current to 240μA. APPLICATIONS Integrated bias control generates gate drive power from the n 48V Telecom and Base Station Power Supplies input supply during start-up and when an output short- n Networking Equipment, Servers circuit occurs, with the addition of a small external SOT23 n Automotive and Industrial Control Systems MOSFET. When in regulation, power is derived from the L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the output for higher effi ciency. property of their respective owners. Protected by U.S. Patents including 5481178, 5847554, 6304066, 6476589, 6580258, 6677210, 6774611. TYPICAL APPLICATIONHigh Effi ciency High Voltage Step-Down ConverterEffi ciency vs Load Current VIN 100 15V TO 100V RON + C 261k 100k IN VIN = 50V 22μF V I IN = 25V ON M3 NDRV 95 ZXMN10A07F VIN = 75V PGOOD BOOST LTC3810 V 90 RNG TG M1 L1 Si7456DP C 0.1μF 10μH SS MODE/SYNC V EFFICIENCY (%) 1000pF OUT SW 12V/6A EXTV 85 SS/TRACK CC DRVCC RFB1 SHDN INTVCC 14k D1 + 80 I SENSE+ TH MBR1100 COUT 0 1 2 3 4 5 6 47pF M2 270μF 200k BG LOAD (A) Si7456DP VFB 3810 TA01b SENSE– 5pF SGND BGRTN RFB2 1μF 1k 3810 TA01 3810fc 1
