LT3482_15 Datasheet, PDF (1/12 Pages) Linear Technology – 90V Boost DC/DC Converter with APD Current Monitor

FEATURES
■ _{High Output Voltage: Up to 90V}
■ _{Integrated Schottky Diodes}
■ _{48V, 280mA Internal Switch}
■ _{High Side APD Current Monitor}
■ _{Adjustable Switching Frequency: 650kHz or 1.1MHz}
■ _{Wide VIN Range: 2.5V to 16V}
■ _{Surface Mount Components}
■ _{Low Shutdown Current: <1µA}
■ _Soft-Start
■ _{Internal Compensation}
■ _{CTRL Pin Allows Output Adjustment with No Polarity}
Inversion
■ _{3mm × 3mm 16-Lead QFN Package}
U
APPLICATIO S
■ _{APD Bias}
■ _{PIN Diode Bias}
■ _{Optical Receivers and Modules}
■ _{Fiber Optic Network Equipment}
LT3482
90V Boost DC/DC
Converter with APD
Current Monitor
DESCRIPTIO
The LT^®3482 is a fixed frequency current mode step-up
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.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
V_IN
5V
OFF ON
10µH
0.1µF
1µF
SW
PUMP
V_IN
MONIN
f_SET LT3482
SHDN
CTRL
GND
V_OUT2
V_OUT1
FB
0.47µF
0.47µF
MON
APD 85V
AT 2.5mA
10nF
10k
0.1µF
0.1µF 1M
14k
V_APD
RIPPLE
100mV/DIV
3482 TA01a
Output Voltage Ripple
500ns/DIV
3482 TA01b
3482fa
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