How to calculate the Saturation Current IS in a NPN Bipolar Transistor?

I am trying manually to calculate the saturation current of the simscape npn bipolar transistor block using the datasheet parameters, but I can not replicate the results comparing them to the matlab calculation of the same current. Using the block help is not helping because it says "The block calculates the saturation current IS from the specified Voltage Vbe value and the corresponding Current Ib for voltage Vbe value when Ic is zero. This is the default method.", I am really confused on how the block reads the datasheet parameters and calculates the saturation current. How can I calculate this current manually?

[praguna manvi]

Hi @Sebastian,

Simscape's "NPN Bipolar Transistor" block uses a variant of the Ebers-Moll equations. You can find detailed information about these equations at the following documentation link:

https://www.mathworks.com/help/sps/ref/npnbipolartransistor.html

Answer 1

[Vinay]

Hi @Sebastian,

The base current is given by the below equation

The NPN transistor uses the parameterization option specified in the datasheet. The intial targets are defined in the "NPN Bipolar Transistor" as

1. Voltage Vbe (Base-emitter voltage when the base current is Ib) 0.55V
2. Current Ib (Base current when the base-emitter voltage is Vbe) is 0.5mA

The transistor calculates the saturation current IS from the specified Voltage Vbe value and the corresponding Current Ib for voltage Vbe value when Ic is zero.

I hope this helps.