LT3905 Datasheet | Linear Technology

Boost DC/DC Converter with APD Current Monitor Features n 65V, 350m A Internal DMOS Switch n Integrated Schottky Diode n 2% Accurate APD Current Monitoring Over the 3µA to 3m A Range n Single Resistor Programs Maximum APD Current n Fast APD Current Limiter with Indicator n Programmable Loss-of-Signal Indicator n CTRL Pin Adjusts Output Voltage n Programmable VIN Undervoltage Lockout n High Efficiency Step-Up Converter n Selectable 1MHz/2MHz Switching Frequency n Internally pensated n Internal Soft-Start n 2.7V to 12V VIN Range n Low Shutdown Current: <1µA Applications n APD Bias n PIN Diode Bias n Optical Receivers and Modules n Fiber Optic Network Equipment Description The LT®3905 is a fixed frequency current-mode step-up converter designed to bias avalanche photodiodes (APD) in optical receivers. The LT3905 Features high side APD current monitoring over four decades of dynamic range with better than 2% relative accuracy over the 3µA to 3m A range. The maximum APD current is programmed with a single resistor, and a fast current limiter with indicator protects the APD during overload conditions. Adjustable output voltage provides dynamic bias control, and an adjustable loss-of-signal indicator flags low APD current. Coupled with the integrated DMOS power switch and Schottky rectifier, the LT3905 provides a pact total solution with few external ponents and low solution cost. Constant switching frequency results in predictable output noise that is easy to filter. The LT3905 is available in the tiny footprint (3mm × 3mm) 16-Lead QFN Package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application VIN 2.7V to 12V VOUT ADJUST VIN 100k Adjustable APD Bias Supply 10µH 1µF EN/UVLO VIN LOS_ADJ f SEL VOUT UP TO 54V 634k 15k CTRL 100k MONIN GND 220n F ILIM 1:10 1:20 1:5 LOS_MON...