Infrared receiver Diode-capacitance and dark current

We recommend that you do not forget some basic parameters of the infrared receiver diode.

1. Dark Current: When the infrared receiving diode is in the terminated state, there is still a current called dark current. This dark current has a slight relationship with the reverse voltage, but it is highly correlated with the temperature. As shown in:

 

2. the infrared receiving diode is vulnerable to interference. It will respond to a certain range of wavelengths:

3. capacitor exists in the infrared receiving diode. That is, the equivalent capacitance between the PN junction. The equivalent capacitor is related to the reverse voltage and the signal frequency. Parameters vary greatly. The following is a comparison of the capacitance of the two receiver diodes of different brands. Therefore, if a high-speed pulse signal is added to the reverse end of the following two receiving diodes, different results can be produced.

The above is the analysis we made when we encountered problems with our colleagues in debugging the infrared circuit.