LTC3246 Wide V Range IN Buck-Boost Charge Pump with Watchdog Timer FEATURES DESCRIPTION n 2.7V 38V Operating Range (42V Abs Max) The LTC 3246 is a switched capacitor buck-boost DC/DC n I = 20A Operating, 1.5A in Shutdown converter with integrated watchdog timer. The device Q n Multimode Buck-Boost Charge Pump (2:1, 1:1, 1:2) produces a regulated output (3.3V, 5V or adjustable) from with Automatic Mode Switching a 2.7V to 38V input. Switched capacitor fractional conver- n 12V to 5V Efficiency = 81% sion is used to maintain regulation over a wide range of n I Up to 500mA input voltage. Internal circuitry automatically selects the OUT n V : Fixed 3.3V, 5V or Adjustable (2.5V to 5V) conversion ratio to optimize efficiency as input voltage and OUT n Ultralow EMI Emissions load conditions vary. No inductors are required. n Engineered for Diagnostic Coverage in ISO 26262 The LTC3246s reset time and watchdog timeout may Systems be set without external components, or adjusted using n Overtemperature, Overvoltage and Short-Circuit external capacitors. A windowed watchdog function is Protection used for high reliability applications. The reset input can n Operating Junction Temperature: 150C Max be used for additional supply monitoring or be configured n POR/Watchdog Controller w/External Timing Control as a pushbutton reset. n Thermally Enhanced 16-Lead MSOP Package Low operating current (20A without load, 1.5A in shut- down) and low external parts count make the LTC3246 APPLICATIONS ideally suited for low power, space constrained automo- tive/industrial applications. The device is short-circuit and n Automotive ECU/CAN Transceiver Supplies overtemperature protected and is available in a thermally n Industrial/Telecom Housekeeping Supplies enhanced 16-lead MSOP package. n Low Power 12V to 5V Conversion All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION Regulated 5V Output with Pushbutton Reset Output Voltage vs Input Voltage 2.2F 5.20 5.15 V = 5V OUT + I UP TO 500mA OUT C C 5.10 V = 2.7V TO 38V V V IN IN OUT 5.05 10F 1F SEL2 OUTS/ADJ 500k 500k 5.00 SEL1 RST LTC3246 C 4.95 BIAS WDI 10F 4.90 RT WT RSTI 4.85 I = 50mA OUT GND I = 500mA OUT 4.80 RESET 3246 TA01a 0 2 4 6 8 10 12 14 16 V (V) IN 3246 TA01b 3246fa 1 For more information www.linear.com/LTC3246 V (V) OUTLTC3246 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2) TOP VIEW V , SEL1, SEL2, WDI ................................. 0.3V to 42V IN WT 1 16 OUTS/ADJ V , OUTS/ADJ, RSTI, WT, RT, BIAS, RST . 0.3V to 6V OUT RT 2 15 GND RSTI 3 14 RST I ........................................................................10mA RST BIAS 4 13 C 17 SEL2 5 12 V V Short Circuit Duration ............................. Indefinite OUT OUT + V 6 11 C IN SEL1 7 10 WDI Lead Temperature (Soldering, 10 sec) ...................300C BIAS 8 9 V IN Operating Junction Temperature Range (Notes 3, 4) MSE PACKAGE (E-Grade/I-Grade) .................................. 40 to 125C 16-LEAD PLASTIC MSOP (H-Grade) ...............................................40 to 150C T = 150C, = 40C/W JMAX JA (MP-Grade) ............................................55 to 150C EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range ......................65 to 150C ORDER INFORMATION