LT3905
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LT3905

Boost DC/DC Converter with APD Current Monitor

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Part Details
Part Models 4
1ku List Price Starting From $3.07
Features
  • 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
Additional Details
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The LT3905 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.

Applications

  • APD Bias
  • PIN Diode Bias
  • Optical Receivers and Modules
  • Fiber Optic Network Equipment
Part Models 4
1ku List Price Starting From $3.07

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Documentation

Documentation

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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Product Lifecycle

PCN

Apr 11, 2019

- 19_0067

Notification of Wafer Fab Location Change for 0.35 BCD Process

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Part Models

Product Lifecycle

PCN

Apr 11, 2019

- 19_0067

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Notification of Wafer Fab Location Change for 0.35 BCD Process

LT3905EUD#PBF

PRODUCTION

LT3905EUD#TRPBF

PRODUCTION

LT3905IUD#PBF

PRODUCTION

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PRODUCTION

Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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DC1956A

LT3905 Demo Board | Boost with APD Current Monitor, 2.7V ≤ VIN ≤ 12V, VOUT = 50V @ 2mA

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DC1956A

LT3905 Demo Board | Boost with APD Current Monitor, 2.7V ≤ VIN ≤ 12V, VOUT = 50V @ 2mA

LT3905 Demo Board | Boost with APD Current Monitor, 2.7V ≤ VIN ≤ 12V, VOUT = 50V @ 2mA

Product Detail

Demonstration circuit 1956A features the LT3905, a boost DC/DC Converter with APD current monitor that comes in a 3mm × 3mm QFN package. This demo board is designed to convert a 2.7V to 12V input to a 50V output at 2mA. The LT3905 is equipped with indicators for monitoring APD current, overload, and loss-of-signal (LOS) conditions, which can easily be changed with their respective resistors. In addition, the output voltage can be adjusted via the CTRL pin. DC1956A is designed for 1MHz operation but can also be programmed for 2MHz by moving jumper JP2.

Tools & Simulations

Tools & Simulations 1

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, 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.

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