| Varactors |
| --------- |
| |
| Spice Model Information |
| ~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| - Cell Name: :cell:`capbn_b` |
| - Model Name: :model:`sky130_fd_pr__cap_var_lvt`, :model:`sky130_fd_pr__cap_var_hvt` |
| - Model Type: subcircuit |
| |
| Operating Voltages where SPICE models are valid |
| |
| - :math:`|V_0 – V_1| = 0` to 2.0V |
| |
| Details |
| ~~~~~~~ |
| |
| The following devices are available; they are subcircuits with the N-well to P-substrate diodes built into the model: |
| |
| - :model:`sky130_fd_pr__cap_var_lvt` - low VT PMOS device option |
| - :model:`sky130_fd_pr__cap_var_hvt` - high VT PMOS device option |
| |
| The varactors are used as tunable capacitors, major e-test parameters are listed below. Further details on the device models and their usage are in the SKY130 process Family Spice Models (002-21997), which can be obtained from SkyWater upon request. |
| |
| |
| .. include:: cap_var-table0.rst |
| |
| |
| |
| There is no equivalent varactor for 5V operation. The NHV or PHV devices should be connected as capacitors for use at 5V. |
| |
| The symbols for the varactors are shown below: |
| |
| |symbol-cap_var-a| |symbol-cap_var-b| |
| |
| The cross-section of the varactor is shown below: |
| |
| |cross-section-cap_var| |
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| .. |symbol-cap_var-a| image:: symbol-cap_var-a.svg |
| .. |symbol-cap_var-b| image:: symbol-cap_var-b.svg |
| .. |cross-section-cap_var| image:: cross-section-cap_var.svg |
| |
