Component and Pin Properties for SPICE simulation
The following properties are provided in eCADSTAR for operation with the analog simulator.
SPICE Element Name / SPICE Element Header: if an element name is set, then the name overrides the component’s reference designator for the simulator. If an element header is set, then the character is prefixed to the component’s reference designator for the simulator. The SPICE Element Name property takes precedence over the SPICE Element Header property. This is beneficial, as SPICE identifies the device type that is used, based on the head character of its reference designator or the element name.
For example, IC is identified as a ‘Current Source’, therefore applying a different element name, or applying a different head character. This changes the device type for the component. The relationship between device type and head character is shown below.
| Device Type | Head Character |
|---|---|
| Resistor | R |
| Capacitor | C |
| Coil (Inductor) | L |
| Lossless transmission line | T |
| Diode | D |
| BJT | Q |
| JFET | J |
| MOSFET | M |
| Voltage supply | V |
| Current source | I |
| Subcircuit | X |
- SPICE Simulation Value: a part property in eCADSTAR which defines the electrical characteristics of passive elements. It provides the resistance value (Ohm), capacitance value (F), or inductance value (H) of resistors, capacitors and inductors. The value specified for the SPICE Simulation Value property takes precedence over the part property value.
- SPICE Model Name: a dedicated property for the LTspice application which defines the electrical characteristics of active elements. It provides the device model name for analyzing active elements such as transistors, or different types of IC. The device model must be added in the Include Files in the Application Settings dialog to be used within the analog unit.
- SPICE Substrate Connection Node: a dedicated part property for the LTspice application. When creating a schematic, to specify the object that is connected to the substrate for a symbol that has three terminals (BJT, JFET, MOSFET), enter the connected net name.
- SPICE Parameter 1-10: dedicated properties for the SPICE Controller, which define supplementary electrical characteristics for SPICE. The items that you can set vary, depending on the type of element. For example, for passive elements you can set temperature coefficients (up to secondary coefficients). For active elements, you can set physical information on semiconductors. Many of these can be omitted. See SPICE Parameter Characteristics for further details.
- SPICE Pin Number: this value must match the one defined in the Device Model. This property defines which model pin is used on each pin of the component. If this is not defined, then the pin ID property is referenced for the pin mapping.
The detailed properties listed above can be defined at a Part level within the eCADSTAR Library. This allows known good property references to be defined for commonly-used components, and simulation parameters. This reduces development time by avoiding the need to populate the property value for each design instance.
SPICE Parameters Characteristics
You can set SPICE component characteristics within SPICE parameters 1-10. All available parameters for SPICE components are listed in the LTspice Help.
