The LT3482 is a fixed frequency current mode step-up DC/DC converter with voltage doubler designed to bias avalanche photodiodes (APDs) in optical receivers. It can provide up to 90V output. The LT3482 features high side APD current monitoring with better than 10% relative accuracy over the entire temperature range. The integrated power switch, Schottky diodes and APD current monitor allow a small converter footprint and low solution cost. Constant switching frequency results in predictable output noise that is easy to filter. The inductor-based topology ensures an input free from switching noise. An integrated high side current monitor produces a current proportional to APD current with better than 10% relative accuracy over four decades of dynamic range in the input range of 250nA to 2.5mA. This current can be used as a reference to provide a digitally programmed output voltage via the CTRL pin. The LT3482 is available in the tiny footprint (3mm x 3mm) 16-lead QFN package.