Hi Analog Devices Team!
Quick question for you - Is there any spice model for ADPD4100 that I can use in simulation programs like LTspice?
Thank you very much!
I will measure SpO2 (PPG Signal) using ADPD4100 and I want to smulate this situation in LTspice but since ADPDP4100 does not have a Spice model and I do not know what type of Opamps are used in the AFE part of the ADPD4100, I am stuck. What is your suggestion?
The ADPD4100 has trans-impedance amplifiers (TIA) which measure the photocurrent of the photodiode (PD). There are a few specifications of analog front end (AFE) that are related to the SpO2 measurement, including ambient light rejection (ALR) capability, SNR (typically listed in datasheet DC SNR), current headroom/TIA gain, etc. The ADPD4100 has a unique architecture for ALR. The SNR can be tuned with different operation modes, number of LED pulses, LED current. LED current is associated with photocurrent headroom and the TIA gain needs to be adjusted accordingly.
While the performance of SpO2 measurement varies significant at different body locations, the optomechanical design, such as LED/PD spacing, blocking the direct path from LED to PD, and IR wavelength, plays important role in the performance of the SpO2 measurement.