Emitter-Coupled Logic Element Simulation

bjtex09.in : Emitter-Coupled Logic Element Simulation

Requires: S-Pisces/MixedMode
Minimum Versions: Atlas 5.28.1.R

This simulation shows a transient process of gate switching in an ECL circuit. A SPICE-like circuit description is used by Atlas/MIXEDMODE to specify two ECL inverters. Two NPN transistors modeled using device simulation are included in the circuit alongside two devices simulated using a simple SPICE model. This example shows:

  • Specification of an NPN device using Atlas syntax
  • Specification of an ECL inverter circuit using MIXEDMODE netlist syntax.
  • Inclusion of two SPISCES devices within the SPICE circuit.
  • Specification of device simulation models and parameters in MIXEDMODE syntax
  • Simulation of the DC initial bias point
  • Simulation of transient switching characteristics

This example file consists of three runs. The first uses Atlas syntax to define the NPN device geometry, mesh and doping, the second sets up the MIXEDMODE circuit to simulate the initial DC bias point, the third performs the transient circuit simulation using Atlas/MIXEDMODE.

The first run uses Atlas syntax to define the NPN structure. There are two identical NPN devices in the ECL circuit. Both devices can be loaded from a single mesh file bjtex09_0.str .

The second run starts with a netlist description of the ECL circuit. For details of the syntax used in MIXEDMODE, see the MIXEDMODE section of Atlas Manual. The key non-standard element in the circuit is the Atlas device. These are circuit elements where Atlas device simulation is used to give the terminal characteristics as opposed to a SPICE model equation. The primitives letter a is used to identify these devices. In this example there are two such primitives; ai and an. There are also two more NPN bipolar transistors simulated using the SPICE model modbjt. These are labeled qi and qn.

After the .end statement, regular SPISCES syntax is used to define parameters for the device simulation. models is used to set the physical models to be used in each of the devices to be modeled by device simulation. Note the use of the device=<name> parameter. This is compulsory in MIXEDMODE simulation to identify the device to which these parameters are applied. This is true even if only one device simulation element exists in the circuit.

To load and run this example, select the Load button in DeckBuild > Examples. This will copy the input file and any support files to your current working directory. Select the Run button in DeckBuild to execute the example.