125 lines
4.4 KiB
ReStructuredText
125 lines
4.4 KiB
ReStructuredText
Parasitic Layout Extraction
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===========================
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This table list layers and contacts included in SPICE models, and parasitic layers include in the AssuraLayout Extraction.
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The modeled columns indicate sheets and contacts that are parasitic resistance/capacitance included in the model extraction measurements.
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The CAD columns indicate sheets and contacts that are parasitics included in the schematic/layout RCX from Assura.
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.. csv-table:: Parasitic Extraction Table
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:file: rcx/rcx-all.tsv
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:header-rows: 2
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:stub-columns: 1
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:delim: U+0009
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.. note:: The models includes M1/M2 capacitance. As a result of RCX extraction limitation M1/M2 routing over the varactor will have no capacitance extraction.
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Routing and placement of devices over or under Precision resistors (xhrpoly_X_X) should be avoided.
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The parasitic capacitance between 3-terminal MIMC and any routing/devices is not included in layout RCX, except M3 by 1 snap grid width.
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No artificial fringing capacitance is extracted for MIMC M2/M3 due to CAD algorithm after CAPM sizing.
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The parasitic capacitance between Precision resistors (xhrpoly_X_X) and any routing/devices is not included in layout RCX.
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S8Q-5R is not supported for RF ESD diode RCX blocking.
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The ``areaid:substratecut`` will be extracted as a 0.123 ohm two terms resistor.
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Resistance Rules
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----------------
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.. todo:: This table should be rendered like the periphery rules.
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.. csv-table:: Table of resistance rules
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:file: rcx/resistance-rules.csv
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:stub-columns: 1
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Resistance Values
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-----------------
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This section includes tables of basic resistance values for SKY130.
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Further data can be found in the `"SKY130 Stackup Capacitance Data" spreadsheet`_.
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.. csv-table:: Table - Resistances
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:file: rcx/resistance-values.tsv
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:header-rows: 1
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:delim: U+0009
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Capacitance Rules
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-----------------
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.. todo:: This table should be rendered like the periphery rules.
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.. csv-table:: Table of capacitance rules
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:file: rcx/capacitance-rules.csv
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:stub-columns: 1
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Capacitance Values
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------------------
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This section includes tables of basic capacitance values for SKY130.
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Further data can be found in the `"SKY130 Stackup Capacitance Data" spreadsheet`_.
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.. _"SKY130 Stackup Capacitance Data" spreadsheet: https://docs.google.com/spreadsheets/d/1N9To-xTiA7FLfQ1SNzWKe-wMckFEXVE9WPkPPjYkaxE/edit#gid=226894802
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Basic Capacitance - Fringe Downward
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Fringe capacitances are a constant value per unit length and are approximations. Determined by creating a layout with a 5um x 10um rectangle of each layer over or under a much larger rectangle of the other layer. The fringe capacitance computed from the total given minus the parallel plate capacitance.
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"downward direction" means that the larger plate is below the 5um x 10um plate.
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The layer in the first column is always the layer with the 5um x 10um plate.
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.. csv-table:: Table - Capacitance - Fringe Downward
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:file: rcx/capacitance-fringe-downward.tsv
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:header-rows: 1
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:delim: U+0009
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Basic Capacitance - Fringe Upward
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Fringe capacitances are a constant value per unit length and are approximations. Determined by creating a layout with a 5um x 10um rectangle of each layer over or under a much larger rectangle of the other layer. The fringe capacitance computed from the total given minus the parallel plate capacitance.
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"upward direction" means that the larger plate is above the 5um x 10um plate.
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The layer in the first column is always the layer with the 5um x 10um plate.
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.. csv-table:: Table - Capacitance - Fringe Upward
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:file: rcx/capacitance-fringe-upward.tsv
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:header-rows: 1
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:delim: U+0009
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Basic Capacitance - Parallel
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.. csv-table:: Table - Capacitance - Parallel
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:file: rcx/capacitance-parallel.tsv
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:header-rows: 1
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:delim: U+0009
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Discrepencies
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-------------
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Non-precision poly resistors
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These resistors do not extract capacitance to substrate.
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This needs to be accounted for manually by using ICPS_0150_0210 (cap per perimeter), and ICPS_2000_4000 (cap per area).
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Un-shielded VPP's
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Any routing above an un-shielded VPP will not be extracted.
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The impact of this on total capacitance and parasitic capacitance is already comprehended in the model corners, however, cross-talk is not modeled. Also, parasitic cap is routed to ground and this may not be ideal for the scenario.
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The parasitic cap can be estimated using RescapWeb.
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