We present for the first time multi-scale modeling of self-heating effects in conventional MOSFET devices in a common-source and common-drain configurations in which one of the devices is the device under test (DUT) and the other device is the sensor. Via comparisons to experimental measurements performed at IMEC, we are able to uncover the temperature of the hot spot. This is also the first study in which a circuit with two transistors is being simulated using thermal particle-based device simulations.