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Vertical Parallel Plate (VPP) capacitors
----------------------------------------
Spice Model Information
~~~~~~~~~~~~~~~~~~~~~~~
- Cell Name: :cell:`sky130_fd_pr__cap_vpp_XXpXxYYpY_{MM}(_shield(SS)*)(_float(FF)*)(_(VVVV))`
- Model Names: :model:`sky130_fd_pr__cap_vpp_*`
- X and Y are size dimentions
- MM refers to the layers which are used for the capacitance
- SS refers to the layers which are used as shields (`noshield` when no shield is used)
- FF refers to the layers which are floating.
- VVVVV refers to the "variant" when there are multiple devices of the same configuration
Operating Voltages where SPICE models are valid
- :math:`|V_{c0} – V_{c1}| = 0` to 5.5V
Details
~~~~~~~
The VPP caps utilize the tight spacings of the metal lines to create capacitors using the available metal layers. The fingers go in opposite directions to minimize alignment-related variability, and the capacitor sits on field oxide to minimize silicon capacitance effects. A schematic diagram of the layout is shown below:
.. todo::
M3
**M2**
LI
M1
LAYOUT of M2, M3, M4
LAYOUT of LI and M1 (with POLY sheet)
**POLY**
**M4**
These capacitors are fixed-size, and they can be connected together to multiply the effective capacitance of a given node. There are two different constructions.
Parallel VPP Capacitors
^^^^^^^^^^^^^^^^^^^^^^^
These are older versions, where stacked metal lines run parallel:
- :model:`sky130_fd_pr__cap_vpp_08p6x07p8_m1m2_noshield` (M1 \|\| M2 only, 7.84 x 8.58)
- :model:`sky130_fd_pr__cap_vpp_04p4x04p6_m1m2_noshield_o2` (M1 \|\| M2 only, 4.38 x 4.59)
- :model:`sky130_fd_pr__cap_vpp_02p4x04p6_m1m2_noshield` (M1 \|\| M2 only, 2.19 x 4.59)
- :model:`sky130_fd_pr__cap_vpp_04p4x04p6_m1m2_noshield` (M1 :sub:`┴` M2, 4.4 x 4.6, 4 quadrants)
- :model:`sky130_fd_pr__cap_vpp_11p5x11p7_m1m2_noshield` (M1 :sub:`┴` M2, 11.5 x 11.7, 4 quadrants)
- :model:`sky130_fd_pr__cap_vpp_44p7x23p1_pol1m1m2m3m4m5_noshield`
- :model:`sky130_fd_pr__cap_vpp_02p7x06p1_m1m2m3m4_shieldl1_fingercap` (M1 \|\| M2 \|\| M3 \|\| M4, 2.7 x 5.0)
- :model:`sky130_fd_pr__cap_vpp_02p9x06p1_m1m2m3m4_shieldl1_fingercap2` (M1 \|\| M2 \|\| M3 \|\| M4, 2.85 x 5.0)
- :model:`sky130_fd_pr__cap_vpp_02p7x11p1_m1m2m3m4_shieldl1_fingercap` (M1 \|\| M2 \|\| M3 \|\| M4, 2.7 x 10.0)
- :model:`sky130_fd_pr__cap_vpp_02p7x21p1_m1m2m3m4_shieldl1_fingercap` (M1 \|\| M2 \|\| M3 \|\| M4, 2.7 x 20.0)
- :model:`sky130_fd_pr__cap_vpp_02p7x41p1_m1m2m3m4_shieldl1_fingercap` (M1 \|\| M2 \|\| M3 \|\| M4, 2.7 x 40.0)
The symbol for these capacitors is shown below. The terminals c0 and c1 represent the two sides of the capacitor, with b as the body (sub or well).
|symbol-cap_vpp-parallel|
Perpendicular VPP Capacitors
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
These are newer versions, where stacked metal lines run perpendicular and there are shields on top and bottom:
- :model:`sky130_fd_pr__cap_vpp_11p5x11p7_l1m1m2m3m4_shieldm5` (11.5x11.7, with M5 shield)
- :model:`sky130_fd_pr__cap_vpp_11p5x11p7_l1m1m2m3m4_shieldpom5` (11.5x11.7, with poly and M5 shield)
- :model:`sky130_fd_pr__cap_vpp_11p5x11p7_m1m2m3m4_shieldl1m5` (11.5x11.7, with LI and M5 shield)
- :model:`sky130_fd_pr__cap_vpp_04p4x04p6_m1m2m3_shieldl1m5_floatm4` (4.4x4.6, M3 float, LI / M5 shield)
- :model:`sky130_fd_pr__cap_vpp_08p6x07p8_m1m2m3_shieldl1m5_floatm4` (8.6x7.9, M3 float, LI / M5 shield)
- :model:`sky130_fd_pr__cap_vpp_11p5x11p7_m1m2m3_shieldl1m5_floatm4` (11.5x11.7, M3 float, LI / M5 shield)
- :model:`sky130_fd_pr__cap_vpp_11p5x11p7_l1m1m2m3_shieldm4` (11.5x11.7, with M4 shield)
- :model:`sky130_fd_pr__cap_vpp_06p8x06p1_l1m1m2m3_shieldpom4` (6.8x6.1, with poly and M4 shield)
- :model:`sky130_fd_pr__cap_vpp_06p8x06p1_m1m2m3_shieldl1m4` (6.8x6.1, with LI and M4 shield)
- :model:`sky130_fd_pr__cap_vpp_11p3x11p8_l1m1m2m3m4_shieldm5` (11.5x11.7, over 2 :model:`sky130_fd_pr__nfet_05v0_nvt` of 10/4 each)
The symbol for these capacitors is shown below. The terminals c0 and c1 are the two capacitor terminals, top represents the top shield and sub the bottom shield.
|symbol-cap_vpp-perpendicular|
The capacitors are fixed-size elements and must be used as-is; they can be used in multiples.
.. include:: cap_vpp-table0.rst
.. |symbol-cap_vpp-parallel| image:: symbol-cap_vpp-parallel.svg
.. |symbol-cap_vpp-perpendicular| image:: symbol-cap_vpp-perpendicular.svg