Ngspice - status update, and degradation simulation

• Speaker(s): Holger Vogt
• email: holger.vogt@uni-due.de
• other information: ngspice web pages

The talk will present the recent developments in ngspice towards release ngspice-45, which is due in July 2025. Examples for new/improved features are: Enable co-simulation with digital devices coded in VHDL, with GHDL as intermediate compiler; improve the VBIC bipolar model to be used in the IHP Open PDK; improve event node plotting.

Then I will present some activities on degradation simulation. A model has been attached to ngspice using scripting to simulate the degradation of MOS devices over time. Some simulation results will be shown, based on devices from the the IHP open PDK.

These models will set the ground for simulating circuits in a radiation environment, as found during space missions. While they are still under development for total ionizing dose (TID), there are first simulation results available for SEE (single event effects) on CMOS circuits. Ions from space radiation hit a circuit, thus charges are created, which may disturb the circuit (flip bits, create noise). Simulation goal is to identify sensitive nodes, which may then be hardened by design. Some results will be shown.