Convertor chip is biased about photodiodes

Fixed-frequency current-mode step-up DC/DC convertor with built-in voltage doubler is designed to bias avalanche photodiodes in optical receivers.

Available now from Linear Technology, the LT3482 is a fixed-frequency current-mode step-up DC/DC convertor with a built-in voltage doubler designed to bias avalanche photodiodes (APDs) in optical receivers.

The device can deliver an output of up to 90V from inputs ranging from 2.5 to 16V.

The LT3482 features high side APD current monitoring, which offers better than 10% relative accuracy over a -40 to +85C temperature range.

The integrated power switch, Schottky diodes, and APD current monitor are all on a single die, packaged in a tiny 3 x 3mm QFN, providing a tiny solution footprint.

The LT3482's internal 48V, 280mA switch uses a voltage doubler to deliver voltages as high as 90V.

A constant frequency architecture is used to minimise switching noise and is user selectable at either 625kHz or 1.1MHz.

Low output ripple, critical in APD applications, is maintained under 80uV peak-peak without any additional filtering.

The 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 APD input current range of 250nA to 2.5mA.

Additionally, the LT3482 is equipped with both a 1.235V internal reference and an auxiliary reference input (via the control pin), enabling the output voltage to be adjusted while the chip is operating.

Other features include soft-start, internal compensation and thermal shutdown.

The LT3482EUD operates from a 0 to 85C temperature range, whereas the LT3482IUD operates from -40 to +85C.

Both parts are available from stock.

Pricing starts at US $3.45 each for the LT3482EUD and US $4.14 each for the LT3482IUD, both in 1000-piece quantities.

Back to top