POWER LOSS (mW) LT3473/LT3473A Micropower 1A Boost Converter with Schottky and Output Disconnect FEATURES DESCRIPTIO Tiny Solution Size The LT 3473/LT3473A are micropower step-up DC/DC Low Quiescent Current: converters with integrated Schottky diode and output 150A in Active Mode (V = 3.6V, V = 15V, disconnect circuitry in low profile DFN packages. The IN OUT No Load) small package size, high level of integration and the use of 1A in Shutdown Mode tiny SMT components yield a solution size of less than 2 Internal 1A, 36V Switch 50mm . The internal 1A switch allows the device to deliver Integrated Schottky Diode 25V at up to 80mA from a Li-Ion cell, while automatic Burst Integrated PNP Output Disconnect Mode operation maintains efficiency at light load. An Internal Reference Override Pin auxiliary reference input (CTRL) allows the user to over- PGOOD Pin ride the internal 1.25V feedback reference with any lower 25V at 80mA from 3.6V Input value, allowing full control of the output voltage during Auxiliary NPNs for Intermediate operation. A PGOOD pin sinks current when the output Bias Voltages (LT3473A) voltage reaches 90% of final value. Automatic Burst Mode Operation at Light Load The LT3473A includes two NPN transistors for generating Constant Switching Frequency: 1.2MHz intermediate bias voltages from the output and is offered Thermal Shutdown in a 12-lead (4mm 3mm) DFN package. The LT3473 Input Range: 2.2V to 16V does not include these NPNs and is offered in an 8-lead Low Profile (3mm 3mm) DFN Package (LT3473) (3mm 3mm) package. Low Profile (4mm 3mm) DFN Package (LT3473A) U The rugged 36V switch and output disconnect circuitry APPLICATIO S allow outputs up to 34V to be easily generated in a simple boost topology. OLED Bias , LTC and LT are registered trademarks of Linear Technology Corporation. CCD Bias Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO Conversion Efficiency and Power Loss vs Output Current 80 500 V = 3.6V IN V = 15V OUT V OUT 75 400 25V PGOOD OUT 80mA 2.2F CTRL 70 300 6.8H LT3473 V IN SW 3V TO 4.2V CAP 65 200 V IN 2M FB 0.47F SHDN 60 100 GND 100k 4.7F 3473 TA01a 55 0 0.1 1 10 100 OUTPUT CURRENT (mA) 3473 TA01b 3473f 1 EFFICIENCY (%) U ULT3473/LT3473A ABSOLUTE AXI U RATI GS (Note 1) V Voltage ............................................................. 16V CTRL Voltage .......................................................... 10V IN SHDN Voltage .......................................................... 16V NB1, NB2 Voltage ................................................... 36V SW Voltage ............................................................. 36V NE1, NE2 Voltage ................................................... 36V PGOOD Voltage ...................................................... 36V Maximum Junction Temperature ......................... 125C CAP Voltage ............................................................ 36V Operating Temperature Range (Note 2) .. 40C to 85C OUT Voltage ........................................................... 36V Storage Temperature Range ................ 65C to 125C FB Voltage .............................................................. 10V UUW PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART TOP VIEW TOP VIEW NUMBER NUMBER CAP 1 12 SW OUT 2 11 V CAP 1 8 SW IN LT3473EDD LT3473AEDE OUT 2 7 V IN NB1 3 10 SHDN 9 13 CTRL 3 6 SHDN NE1 4 9 PGOOD FB PGOOD 4 5 NB2 5 8 CTRL NE2 6 7 FB DD PART MARKING DE PART MARKING DD PACKAGE 8-LEAD (3mm 3mm) PLASTIC DFN DE PACKAGE 12-LEAD (4mm 3mm) PLASTIC DFN LBJJ 3473A T = 125C, = 43C/ W JMAX JA T = 125C, = 43C/ W EXPOSED PAD (PIN 9) IS GND JMAX JA MUST BE SOLDERED TO PCB (NOTE 3) EXPOSED PAD (PIN 13) IS GND MUST BE SOLDERED TO PCB (NOTE 3) Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25C. A V = 3V, SHDN = 3V, CTRL = 2V, unless otherwise specified. IN PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operation Voltage 2.2 V Maximum Operation Voltage 16 V Supply Current SHDN = 3V, Not Switching 100 A SHDN = 0V 0.1 1 A SHDN Voltage to Enable Chip 1.4 V SHDN Voltage to Disable Chip 0.2 V SHDN Pin Bias Current 2 A FB Voltage 1.235 1.25 1.26 V FB Voltage Line Regulation 3V < V < 16V 0.01 %/V IN FB Pin Bias Current FB = 1.27V 20 nA CTRL to FB Offset CTRL = 0.5V 5 20 mV CTRL Pin Bias Current CTRL = 1V 50 nA FB Threshold for PGOOD CTRL = 2V 1.15 V CTRL = 0.5V 0.40 V PGOOD Current Capacity 100 A 3473f 2 U WWW