The LT3905 from Linear Technology is a fixed frequency, current-mode step-up DC/DC converter designed to bias avalanche photodiodes (APD) in optical receivers. The LT3905 features high side APD current monitoring with over five decades of dynamic range and better than 2% relative accuracy over the 3µA to 3mA range. The maximum APD current is programmed with a single resistor and a fast current limiter with indicator protects the APD during overload conditions.
