| Title: | 555_BJT_EE |
| Package: | DIP8 |
| Description: | Behavioural model of a bipolar transistor implementation of a 555 timer. Intended to be more accurate and less resource hungry than the 'discrete' 555 timer subckt originally used by the EasyEDA Libs symbol but to implement most of the behaviours of a real device. Quiescent and load current drains are modelled. Input and output pin under/overrail and supply over/reverse voltage faults will draw very high currents. Output voltage vs. current is crudely modelled but short circuit current to ground and rail is not. Output rise/fall times are unrealistically fast due to simple switches being used for the totem pole output stage. Output shoot-through current is modelled but is currently disabled since it can contribute to simulation convergence problems and eats up CPU time. Temperature effects are not modelled. Many parameters are derived from the TI datasheet: http://www.ti.com/lit/ds/symlink/ne555.pdf but some are empirically derived from graphed data rather than calculated from given parameters. Developed for EasyEDA by signality.co.uk 161031 |
