The LT3905EUD#PBF is a fixed frequency current-mode step-up converter designed to bias avalanche photodiodes (APD) in optical receivers. The LT3905EUD#PBF features high side APD current monitoring over four decades of dynamic range with better than 2% relative accuracy over the 3μA to 3mA range.
The maximum APD current is programmed with a single resistor, and a fast current limiter with indicator protects the APD during overload conditions. Adjustable output voltage provides dynamic bias control, and an adjustable loss-of-signal indicator flags low APD current.
Coupled with the integrated DMOS power switch and Schottky rectifier, the LT3905EUD#PBF provides a compact total solution with few external components and low solution cost. Constant switching frequency results in predictable output noise that is easy to filter.
The LT3905EUD#PBF is available in the tiny footprint (3mm × 3mm) 16-Lead QFN Package.
Feature
- 65V, 350mA Internal DMOS Switch
- Integrated Schottky Diode
- 2% Accurate APD Current Monitoring Over the 3μA to 3mA Range
- Single Resistor Programs Maximum APD Current
- Fast APD Current Limiter with Indicator
- Programmable Loss-of-Signal Indicator
- CTRL Pin Adjusts Output Voltage
- Programmable VIN Undervoltage Lockout
- High Efficiency Step-Up Converter
- Selectable 1MHz/2MHz Switching Frequency
- Internally Compensated
- Internal Soft-Start
- 2.7V to 12V VIN Range
- Low Shutdown Current: <1μA
Applications
- APD Bias
- PIN Diode Bias
- Optical Receivers and Modules
- Fiber Optic Network Equipment
