Rev A Locked Architecture Details
Run AD5940 datasheet limits review only.
Do not modify schematic wiring.
Do not add components.
Do not change nets.
Review the AD5940 placeholder against datasheet/application-circuit requirements and identify what must be locked before PCB layout.
Check:
- Rail requirements:
- AVDD valid voltage range
- DVDD valid voltage range
- IOVDD / digital I/O rail requirement
- REG_1V8 role
- whether DVDD_AD5940 may remain tied to MCU_3V3: yes/no/uncertain
- whether separate 1.8 V rail placeholder is required: yes/no/uncertain
- SPI/logic compatibility:
- whether STM32L552 3.3 V SPI can directly connect to AD5940: yes/no/uncertain
- whether level shifting may be required: yes/no/uncertain
- BioZ/EIS pins:
- map placeholder nets to likely AD5940 pins/functions: AD5940_I_PLUS_PATH AD5940_I_MINUS_PATH AD5940_V_PLUS_PATH AD5940_V_MINUS_PATH AD5940_CURRENT_SENSE_P AD5940_CURRENT_SENSE_N AD5940_EXC_MON AD5940_AIN_MON
- Application-circuit blockers:
- required external references
- required RTIA/RLOAD/RCAL components
- required clock/crystal if any
- required decoupling not already represented
- required reset/interrupt/control pins
- Pre-layout decision: Choose one: A. Keep AD5940 as placeholder only B. Add separate 1.8 V LDO placeholder C. Add level-shifter placeholder only D. Split DVDD_AD5940 from MCU_3V3 E. Need human datasheet review before schematic changes
Report only:
- AD5940 rail blockers
- SPI/logic blockers
- missing application-circuit components
- recommended next schematic action
- whether current AD5940 section is safe for PCB layout: yes/no
Thought for 7 sec
I’ll run a read-only AD5940 datasheet-limits review against the current placeholder section, check rails, SPI logic, pin-role mapping, and application-circuit gaps, then report only the blockers and next action.
Worked for 1 min 10 sec
STOP
Let me think about this...
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Calibration Bank Verification Report
Date: 2026-05-22
Project: Bench EchoSpec AFE V7
Scope: Read-only verification pass of the calibration bank
Overall Status
- Calibration bank structures requested by the user are present.
- CAL_COM exists and no E8 net label or E8 component label was found.
- The requested resistor and capacitor values are present.
- All calibration capacitors currently carry C0G/NP0 metadata.
- No muxes, electrodes, or AD5940 components were found in the schematic.
- There are review issues still present, primarily PCB airwires and floating net-portal pins.
1. CAL_COM / E8 Check
- CAL_COM net exists: PASS
- E8 net label exists: FAIL NOT FOUND (desired result)
- E8 component/designator exists: FAIL NOT FOUND (desired result)
- Conclusion: CAL_COM exists and is not labeled E8.
2. Required Calibration Nets
All requested nets were found:
- CAL_100R: PASS
- CAL_1K: PASS
- CAL_10K: PASS
- CAL_1K_PAR_10NF: PASS
- CAL_10K_PAR_1NF: PASS
- CAL_SERIES: PASS
- CAL_SERIES_MID: PASS
- CAL_DUMMY_RC: PASS
- CAL_DUMMY_MID: PASS
3. Component Value and Connectivity Checks
Simple resistor standards
- R_CAL_100R = 100 ohms between CAL_100R and CAL_COM: PASS
- R_CAL_1K = 1000 ohms between CAL_1K and CAL_COM: PASS
- R_CAL_10K = 10000 ohms between CAL_10K and CAL_COM: PASS
Parallel RC standards
- R_CAL_1K_PAR_10NF = 1000 ohms between CAL_1K_PAR_10NF and CAL_COM: PASS
- C_CAL_1K_PAR_10NF = 10 nF, dielectric C0G/NP0, between CAL_1K_PAR_10NF and CAL_COM: PASS
- R_CAL_10K_PAR_1NF = 10000 ohms between CAL_10K_PAR_1NF and CAL_COM: PASS
- C_CAL_10K_PAR_1NF = 1 nF, dielectric C0G/NP0, between CAL_10K_PAR_1NF and CAL_COM: PASS
Series + parallel branch standard
- R_CAL_SERIES_100R = 100 ohms between CAL_SERIES and CAL_SERIES_MID: PASS
- R_CAL_SERIES_1K = 1000 ohms between CAL_SERIES_MID and CAL_COM: PASS
- C_CAL_SERIES_10NF = 10 nF, dielectric C0G/NP0, between CAL_SERIES_MID and CAL_COM: PASS
- Parallel condition for R_CAL_SERIES_1K and C_CAL_SERIES_10NF between CAL_SERIES_MID and CAL_COM: PASS
Dummy RC placeholder network
- R_CAL_DUMMY_SERIES = 1000 ohms between CAL_DUMMY_RC and CAL_DUMMY_MID: PASS
- R_CAL_DUMMY_PAR = 10000 ohms between CAL_DUMMY_MID and CAL_COM: PASS
- C_CAL_DUMMY_PAR = 100 nF, dielectric C0G/NP0, between CAL_DUMMY_MID and CAL_COM: PASS
- Parallel condition for R_CAL_DUMMY_PAR and C_CAL_DUMMY_PAR between CAL_DUMMY_MID and CAL_COM: PASS
4. Forbidden Capacitor Types in Calibration Bank
Checked calibration capacitors present in the project:
- C_CAL_1K_PAR_10NF: Ceramic, Dielectric = C0G/NP0
- C_CAL_10K_PAR_1NF: Ceramic, Dielectric = C0G/NP0
- C_CAL_SERIES_10NF: Ceramic, Dielectric = C0G/NP0
- C_CAL_DUMMY_PAR: Ceramic, Dielectric = C0G/NP0
No capacitor in the calibration bank was found with:
- X7R
- X5R
- Y5V
- Z5U
- Electrolytic
- Tantalum
Result: PASS
5. Forbidden Functional Parts Check
Schematic summary showed only:
- Net Portal
- Generic Resistor
- Generic Capacitor
Not found:
- muxes: PASS
- electrodes: PASS
- AD5940: PASS
- E8: PASS
6. Exceptions / Issues Found
A. Duplicate net portal labels / extra aliases
There is only one logical net for each requested calibration net, but some nets have multiple net-portal instances attached to the same logical net. This is not an electrical short by itself, but it creates duplicate visible labels/aliases in the schematic.
Observed extra portal aliases:
- CAL_COM has many portal instances
- CAL_SERIES and CAL_SERIES_MID each have multiple portal instances
- CAL_DUMMY_RC and CAL_DUMMY_MID each have multiple portal instances
- CAL_1K_PAR_10NF is represented by portal labels named
R_CAL_1K_PAR_10NF P1 - C_CAL_1K_PAR_10NF P1 - CAL_10K_PAR_1NF is represented by portal labels named
R_CAL_10K_PAR_1NF P1 - C_CAL_10K_PAR_1NF P1
Impact:
- Logical connectivity is still correct.
- Schematic readability is degraded.
- These count as accidental duplicate net labels/aliases from a documentation perspective.
B. Floating-net warnings on portal pins
Electrical review reports floating pin warnings on:
- CAL_SERIES:P1
- CAL_SERIES_MID:P1
- CAL_DUMMY_RC:P1
- CAL_DUMMY_MID:P1
Interpretation:
- These are exposed calibration nodes represented by portals.
- Electrically they are expected to be available for later connection.
- They are still unresolved ERC warnings at this time.
C. PCB airwires / unresolved layout connectivity
Design review reports 16 airwire errors. These are layout-level unresolved routing issues, not schematic netlist shorts.
Interpretation:
- The schematic connectivity exists.
- The PCB/layout side is not fully routed or synchronized for these connections.
- This remains an unresolved review issue.
D. Manufacturing metadata gaps
Manufacturing review reports missing manufacturer part numbers on all 13 generic passives in the calibration bank.
Interpretation:
- This does not invalidate the schematic topology.
- It is still an unresolved manufacturing review issue.
E. Incorrect values / missing components / accidental schematic shorts
- Incorrect values found: NONE
- Missing requested calibration components: NONE
- Accidental schematic shorts between distinct calibration nets: NONE found
Final Summary
Passed
- Requested calibration nets exist
- Requested component values are correct
- Requested resistor/capacitor topology is correct
- Calibration capacitors are all marked C0G/NP0
- No muxes, electrodes, AD5940, or E8 were found
- No accidental schematic shorts were found
Open Issues
- Duplicate/extra net-portal labels exist on several calibration nets
- 4 floating-pin ERC warnings on portal nodes
- 16 PCB airwire review errors
- 13 missing MPN manufacturing review errors
Recommendation
If the next step is cleanup, the highest-value fixes are:
- Remove duplicate/alias net portals so each calibration net has one intentional visible label set.
- Decide whether the exposed calibration nodes should remain floating or be marked intentionally for ERC handling.
- Resolve the PCB airwires if layout continuity matters yet.
- Add MPNs if you want the bank to be manufacturing-ready.
Overall Status
1. CAL_COM / E8 Check
2. Required Calibration Nets
3. Component Value and Connectivity Checks
Simple resistor standards
Parallel RC standards
Series + parallel branch standard
Dummy RC placeholder network
4. Forbidden Capacitor Types in Calibration Bank
5. Forbidden Functional Parts Check
6. Exceptions / Issues Found
A. Duplicate net portal labels / extra aliases
B. Floating-net warnings on portal pins
C. PCB airwires / unresolved layout connectivity
D. Manufacturing metadata gaps
E. Incorrect values / missing components / accidental schematic shorts
Final Summary
Passed
Open Issues
Recommendation
