LT3482

1

3482fa

90V Boost DC/DC

Converter with APD

Current Monitor

The LT

DC/DC converter with voltage doubler designed to bias

avalanche photodiodes (APDs) in optical receivers. It can

provide up to 90V output. The LT3482 features high side

APD current monitoring with better than 10% relative ac-

curacy over the entire temperature range. The integrated

power switch, Schottky diodes and APD current monitor

allow a small converter footprint and low solution cost.

Constant switching frequency results in predictable output

noise that is easy to filter. The inductor-based topology

ensures an input free from switching noise. An 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 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 LT3482 is available in the tiny footprint

(3mm

× 3mm) 16-lead QFN package.

Inversion

× 3mm 16-Lead QFN Package

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

1

µF

0.1

µF

1M

MONIN

SHDN

CTRL

GND

FB

SW

PUMP

LT3482

MON

APD

OFF ON

5V

14k

85V

AT 2.5mA

3482 TA01a

0.47

µF

0.47

µF

0.1

µF

10k

10nF

0.1

µF

10

µH

RIPPLE

100

mV/DIV

500ns/DIV

3482 TA01b

Output Voltage Ripple