EDA Skillpack
Public Made by Adomby adom
All skills for all EDA capabilities across the Adom ecosystem.
name: eda-kelvin-current-sense description: Use when placing or routing shunts and current-sense amplifiers, or reviewing pours near Kelvin sense traces, including a sense return named GND and sense vias crossing copper planes.
Parent skill: eda-engineering
Preserve the measurement path through final copper fill
Source: TI SSZTAD8, Vijay Choudhary, March 2017, differential current-sense routing, net ties and polygon keepouts. Its example uses LM5175 CS/CSG; identify the equivalent pins on the actual device instead of copying those names.
Decisions from the TI article
Route both sense conductors from the intended shunt pickup points to the sensing inputs, even when one conductor shares the GND net name. A general ground-plane connection is not automatically an equivalent measurement return.
Protect the pair during the pour-finishing stage. A previously correct sense trace can acquire an unwanted connection anywhere along its length when same-net ground copper fills around it.
Use an appropriate net-tie scheme or copper-pour keepout to preserve the intended path. With a net tie, the section still named GND also needs protection. With keepouts, protect the entire route and every relevant copper layer around a through-via; a top-only cutout leaves inner-plane connections possible. Inspect the filled result, not just the trace centerlines. See the article's Figures 2–5.
Execute and report
Build a pad-level table: shunt terminal, sense-input pin, power-current connection, intended pickup location, and permitted plane connection. Check the schematic and actual pad/net assignments before editing. A net-tie implementation changes connectivity representation and must be kept consistent between schematic, PCB and validation; do not silently rename nets to satisfy DRC.
At placement, route completion and final refill, inspect the two pickup paths and all via annuli on every copper layer. Re-run this check after copper expansion or rerouting. Record any unexpected same-net contact as a failed measurement-path check even when native DRC reports no error.
Deliver annotated pickup/return geometry, chosen keepout or net-tie treatment, native validation and unresolved device/filter requirements. Use the actual amplifier datasheet for filtering, common-mode range, bandwidth and input limits; this article is not a generic filter-design prescription. For the surrounding power stage, read motor-driver layout.
Full-pad endpoint check
A keepout buffered around a trace centerline can stop at the center of the amplifier pad and leave part of that same-net pad touching a pour. Include the entire sense-input pad and any via annulus, with clearance, in the protected region. Exempt only the intended shunt pickup area. Check the polygon union against full pad shapes, then inspect the native filled result. The independent Astra ESC example records this correction after an otherwise zero-open DRC result.
---
name: eda-kelvin-current-sense
description: Use when placing or routing shunts and current-sense amplifiers, or reviewing pours near Kelvin sense traces, including a sense return named GND and sense vias crossing copper planes.
---
Parent skill: eda-engineering
# Preserve the measurement path through final copper fill
Source: [TI SSZTAD8, Vijay Choudhary, March 2017, differential current-sense routing, net ties and polygon keepouts](https://www.ti.com/document-viewer/lit/html/SSZTAD8/GUID-B8989FC6-7E3F-4B21-8E84-7390293FB0EF). Its example uses LM5175 CS/CSG; identify the equivalent pins on the actual device instead of copying those names.
## Decisions from the TI article
Route both sense conductors from the intended shunt pickup points to the sensing inputs, even when one conductor shares the GND net name. A general ground-plane connection is not automatically an equivalent measurement return.
Protect the pair during the pour-finishing stage. A previously correct sense trace can acquire an unwanted connection anywhere along its length when same-net ground copper fills around it.
Use an appropriate net-tie scheme or copper-pour keepout to preserve the intended path. With a net tie, the section still named GND also needs protection. With keepouts, protect the entire route and every relevant copper layer around a through-via; a top-only cutout leaves inner-plane connections possible. Inspect the filled result, not just the trace centerlines. See the article's Figures 2–5.
## Execute and report
Build a pad-level table: shunt terminal, sense-input pin, power-current connection, intended pickup location, and permitted plane connection. Check the schematic and actual pad/net assignments before editing. A net-tie implementation changes connectivity representation and must be kept consistent between schematic, PCB and validation; do not silently rename nets to satisfy DRC.
At placement, route completion and final refill, inspect the two pickup paths and all via annuli on every copper layer. Re-run this check after copper expansion or rerouting. Record any unexpected same-net contact as a failed measurement-path check even when native DRC reports no error.
Deliver annotated pickup/return geometry, chosen keepout or net-tie treatment, native validation and unresolved device/filter requirements. Use the actual amplifier datasheet for filtering, common-mode range, bandwidth and input limits; this article is not a generic filter-design prescription. For the surrounding power stage, read [motor-driver layout](../eda-motor-driver-layout/SKILL.md).
## Full-pad endpoint check
A keepout buffered around a trace centerline can stop at the center of the amplifier pad and leave part of that same-net pad touching a pour. Include the entire sense-input pad and any via annulus, with clearance, in the protected region. Exempt only the intended shunt pickup area. Check the polygon union against full pad shapes, then inspect the native filled result. The [independent Astra ESC example](../../docs/examples/astra-esc-independent/README.md) records this correction after an otherwise zero-open DRC result.