LT3571
75V DC/DC Converter
for APD Bias
FEATURES DESCRIPTION n The LTВ®3571 is a current mode step-up DC/DC converter
designed to bias avalanche photodiodes (APDs) in optical
receivers with an output voltage up to 75V. The LT3571
features a high side п¬Ѓxed voltage drop APD current monitor with better than 10% relative accuracy over the entire
temperature range. The integrated power switch, Schottky
diode and APD current monitor allow a small solution
footprint and low solution cost. It combines a traditional
voltage loop and a unique current loop to operate as
a constant-current source or constant-voltage source.
The inductor-based topology ensures an input free from
switching noise. The integrated high side current monitor
produces a current proportional to the 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 LT3571
is available in the tiny footprint (3mm Г— 3mm) 16-lead
QFN package. High APD Voltage: Up to 70V
Integrated Schottky Diode
75V, 370mA Internal Switch …