# Extrapolating parameters for SPICE model for a Silicon Photomultiplier

I've been working on a circuit involving a silicon photomultiplier, but I'm having trouble modeling the SiPM in LTspice. I found an article below that shows a proposed model for an SiPM in SPICE:

My problem is that I don't know how to extrapolate parameters for the model, such as the quenching resistance and capacitance as well as the inner junction capacitance and the internal resistance. I'm trying to model it based off of the MicroFJ-60035 SiPM provided by SensL found here:

http://sensl.com/products/j-series/

However, the parameters that they give don't really tell me much about the necessary parameters for the SPICE model directly. How can I get the parameters needed from the datasheet? As a reference, my circuit that I am trying to build is the recommended readout circuit found in the user manual.

• Creating SPICE models for optoelectronic devices isn't always straightforward. Even extracting the appropriate parameters can be an area for research. You can even get a Ph.D. in it. Since neither of the resources you linked actually gives much information without paying a fee or providing contact details, you're not likely to get answers specific to the devices and model you're looking at. – The Photon Apr 21 '17 at 16:50
• It might be useful to provide links that aren't paywalled. – Voltage Spike Apr 21 '17 at 17:40
• Sorry. I was able to download it for free where I'm at. Perhaps this might be a better link: researchgate.net/publication/… – user101402 Apr 21 '17 at 18:16

Secondly: The overvoltage is given in the model as $V_{ov}= V_k-V_{BD}$, in the datasheet its listed as $V_{br} +2.5$ (as an example, its model dependent) and $V_{br}$ is nominally 24.5V.