Let’s look specifically at the Linear Technology LT3571 APD bias generator. If an application requires a high output voltage and 10s of mA of supply current, then the LT3571 would be the ideal solution. The LT3571 operates with VIN up to 20V and VOUT up to 75V and has a 350mA internal switch peak current limit so that even with low VIN voltages, the device can provide, adequate output current. With an integrated Schottky diode and an integrated high side current monitor, the feature rich LT3571 packs a lot of functionality into a small 3mm x 3mm QFN-16 package.