LT3482 90V Boost DC/DC Converter with APD Current Monitor FEATURES DESCRIPTIO High Output Voltage: Up to 90V The LT 3482 is a xed frequency current mode step-up Integrated Schottky Diodes DC/DC converter with voltage doubler designed to bias 48V, 280mA Internal Switch avalanche photodiodes (APDs) in optical receivers. It can High Side APD Current Monitor provide up to 90V output. The LT3482 features high side Adjustable Switching Frequency: 650kHz or 1.1MHz APD current monitoring with better than 10% relative ac- Wide V Range: 2.5V to 16V curacy over the entire temperature range. The integrated IN Surface Mount Components power switch, Schottky diodes and APD current monitor Low Shutdown Current: <1A allow a small converter footprint and low solution cost. Soft-Start Constant switching frequency results in predictable output Internal Compensation noise that is easy to lter. The inductor-based topology CTRL Pin Allows Output Adjustment with No Polarity ensures an input free from switching noise. An integrated Inversion high side current monitor produces a current proportional 3mm 3mm 16-Lead QFN Package to APD current with better than 10% relative accuracy over four decades of dynamic range in the input range of U APPLICATIO S 250nA to 2.5mA. This current can be used as a reference to provide a digitally programmed output voltage via the APD Bias CTRL pin. The LT3482 is available in the tiny footprint PIN Diode Bias (3mm 3mm) 16-lead QFN package. Optical Receivers and Modules , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Fiber Optic Network Equipment All other trademarks are the property of their respective owners. TYPICAL APPLICATIO 0.1F 10H V IN 5V Output Voltage Ripple SW PUMP 1F V MONIN IN f LT3482 SET OFF ON V SHDN OUT2 V APD 0.47F RIPPLE CTRL 0.1F 1M V OUT1 100 V/DIV 0.47F GND FB 85V MON APD 14k AT 2.5mA 10k 10nF 0.1F 3482 TA01b 500ns/DIV 3482 TA01a 3482fa 1 U ULT3482 ABSOLUTE AXI U RATI GS PIN CONFIGURATION (Note 1) TOP VIEW Input Voltage (V ) .................................................... 16V IN V , SW Voltage ....................................................48V OUT1 16 15 14 13 V , PUMP, MONIN, APD Voltage ..........................90V OUT2 NC 1 12 SHDN FB Voltage ...................................................................5V APD 2 11 V IN SHDN, f , CTRL Voltage .........................................16V 17 SET MONIN 3 10 GND MON Voltage .............................................................12V V 4 9 GND OUT2 Operating Temperature Range 5 6 7 8 (Note 2) .................................................... 40C to 85C Maximum Junction Temperature .......................... 125C UD PACKAGE Storage Temperature Range ................... 65C to 125C 16-LEAD (3mm 3mm) PLASTIC QFN T = 125C, = 68C/W, = 4.2C/W JMAX JA JC EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3482EUD PBF LT3482EUD TRPBF LCFG 16-Lead (3mm 3mm) Plastic QFN 0C to 85C LT3482IUD PBF LT3482IUD TRPBF LCFG 16-Lead (3mm 3mm) Plastic QFN 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. For more information on lead free parts, go to: