The LT3571 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 fixed 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 × 3mm) 16-lead QFN package. Applications * APD Bias * PIN Diode Bias * Optical Receivers and Modules * Fiber Optic Network Equipment * High Output Voltage: Up to 75V * Integrated Schottky Diode * 75V, 350mA Internal Switch * High Side Fixed Voltage Drop APD Current Monitor * Adjustable Frequency: 250kHz to 2MHz * Frequency Synchronization * Wide VIN Range: 2.7V to 20V * Constant-Voltage and Constant-Current Regulation * Programmable Current Limit Protection * Surface Mount Components * Low Shutdown Current <1μA * Internal Soft-Start * Internal Compensation * CTRL Pin Allows Output Adjustment with No Polarity Inversion * 3mm × 3mm 16-Lead QFN Package https://elecena.pl/product/805319/75v-dc-dc-converter-for-apd-bias 2009-02-03 https://elecena.pl/product/805319/75v-dc-dc-converter-for-apd-bias 2017-10-09 https://elecena.pl/product/805319/75v-dc-dc-converter-for-apd-bias 2025-01-21