LT3905 - Boost DC/DC Converter with APD Current Monitor
- 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
The LT®3905 is a fixed frequency current-mode step-up converter designed to bias avalanche photodiodes (APD) in optical receivers. The LT3905 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 LT3905 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 LT3905 is available in the tiny footprint (3mm × 3mm) 16-Lead QFN Package.
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
|Buy Now • Request Samples|
Demo BoardsLinear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
|DC1956A||LT3905 Demo Board | Boost with APD Current Monitor, 2.7V ≤ VIN ≤ 12V, Vout = 50V @ 2mA||$125.00|
- APD Bias
- PIN Diode Bias
- Optical Receivers and Modules
- Fiber Optic Network Equipment
People Who Viewed This Product Also Viewed
- LT8471 - Dual Multitopology DC/DC Converters with 2A Switches and Synchronization
- LT3482 - 90V Boost DC/DC Converter with APD Bias Current Monitor
- LT3080 - Adjustable 1.1A Single Resistor Low Dropout Regulator
- LT8705 - 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller
- LT8614 - 42V, 4A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current
- LT3081 - 1.5A Single Resistor Rugged Linear Regulator with Monitors
- LT1763 - 500mA, Low Noise, LDO Micropower Regulators
- LTC6992 - TimerBlox: Voltage-Controlled Pulse Width Modulator (PWM)
- LT3580 - Boost/Inverting DC/DC Converter with 2A Switch, Soft-Start, and Synchronization
- LTC4364 - Surge Stopper with Ideal Diode
Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
To launch a ready to run LTspice demonstration circuit for this part:
- Step 1: If you have not installed LTspice on this computer, download and install LTspice
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu
To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Models for the following parts are available in LTspice: