NTC Probe Wiring for LTC2984
2:11
Planning wiring modifications.
Gathering component links.
Thinking deeply about your request.
Analyzing the schematic.
Formulating a high-level plan.
Gathering project context.
Working on your request.
Analyzing the schematic.
Considering project tools.
Working on your request.
Searching the project.
Searching components and nets.
Searching 4 domains.
Refining search for connections.
Searching 4 domains.
Searching for pin connections.
Searching 3 domains.
Searching 3 domains.
Analyzing wiring connections.
Search complete — 1266 results across 4 domains.
Creating a formal plan.
Working on your request.
Creating a high-level plan.
- Review the interface topology and isolation domains
- Add required support parts: termination, biasing, and decoupling
- Connect controller, isolator, bus, and power nets correctly
- Verify completeness and ERC readiness
- Retrieved schematic context for U14, IC3, and Isolated CAN #1 connector; observed existing nets Net 74/Net 76 connected through R28 to connector pins 1/2.
- Pulled key datasheet requirements:
- ISOW1044: STB tied to GNDIO for normal mode; GNDIO and GND1 must be shorted; GND2 and GISOIN pins must be shorted (optionally via ferrite); VSIN short to VISOOUT; all GISOIN pins shorted; EN/FLT default enabled if floating; decoupling: VDD & VISOOUT need 10nF + >=10uF (47uF recommended), VIO/VISOIN need >=100nF.
- MCP2518FD: TXCAN->transceiver TXD, RXCAN=5k pull-up if used as fault output; implement accordingly.
- Enforce required ground/iso strap connections on IC3:
- Short IC3:GNDIO to IC3:GND1.
- Short IC3:GND2 to IC3:GISOIN_1/2/3 (directly or via ferrite bead option).
- Short IC3:VSIN to IC3:VISOOUT.
- Short IC3:VISOIN to isolated supply (as required by existing power tree).
- Add power decoupling networks:
- For IC3 VDD: add 10nF + 1uF + 10uF (or 47uF) to GND1.
- For IC3 VISOOUT: add 10nF + 1uF + 10uF (or 47uF) to GND2.
- For IC3 VIO and VISOIN: add >=100nF to their respective grounds.
- For U14 VDD: add 100nF to VSS; add bulk cap if missing.
- Add bus termination at connector end:
- Add 120Ω across CANH/CANL, or split termination: 2x60Ω to center node + CSPLIT capacitor to GND2, per ISOW1044 guidance.
- Make termination optionally DNP/jumper if board may not be end-of-bus.
- Add optional protection/EMI parts at connector as needed:
- If using common-mode choke, add TVS to meet IEC ESD requirement (per ISOW1044 datasheet note).
- Run ERC and fix any unconnected pins or isolation-domain mistakes; rename nets from Net 74/76 to CANH/CANL and label isolated rails/grounds consistently.
Started implementing a plan
# Goal
- Wire the isolated CAN interface between Isolated CAN #1 connector, U14 (MCP2518FDT-H/SL), and IC3 (ISOW1044BDFMR), ensuring the inclusion of all required support components such as termination resistors, bias circuits, decoupling capacitors, and other associated passive elements.
# Implementation plan
1. **Review Interface Architecture**
1. Confirm the connection topology of the CAN interface among the Isolated CAN #1 connector, U14, and IC3.
2. Document the required signal paths, power, and ground isolations for the isolated domain.
2. **Identify and Add Supporting Passive Components**
1. Add termination resistors on the CAN bus, typically a 120 Ω resistor at one end, ensuring correct bus termination.
2. Include biasing resistors to maintain the CAN bus idle state as per design recommendations.
3. Select and add decoupling capacitors for both U14 and IC3 for proper power supply filtering.
4. Include any additional supporting resistors and capacitors for signal integrity and option for clock support or filtering if needed.
3. **Connect CAN Interface and Isolation Components**
1. Wire the CAN transceiver signals from U14 to the Isolated CAN #1 connector using proper net connections.
2. Route the isolated signals through IC3 ensuring correct isolation between the CAN bus sides.
3. Validate that the connection of power/ground respects the isolation boundaries as per IC3's datasheet and design guidelines.
4. **Review and Verify Design Integration**
1. Review the schematic for completeness, ensuring that all required supporting components are added.
2. Validate that the isolation domain is properly implemented and the bus signals are free of errors.
3. Perform an Electrical Rule Check (ERC) to verify correct connections and component ratings.
# Success criteria
- The CAN interface wiring correctly interconnects the Isolated CAN #1 connector, U14, and IC3 with all passive components properly added.
- The design includes the required termination, bias, decoupling, and support circuits as per CAN bus isolation guidelines.
- The schematic passes ERC and meets the design requirements for isolated CAN operation.
Task completed.
0:18
Execution stopped by user.
1:25
Analyzing the schematic.
Looking for "termination split termination standby enable fail-safe and CANH CANL external components" in isow1044.pdf
Looking for "VDD decoupling capacitor recommendations and TXCAN RXCAN connection guidance" in External-CAN-FD-Controller-with-SPI-Interface-DS20006027B.pdf
Set System Architecture to "flowchart TD U14["U14 MCP..."
0:10
Set System Architecture to "flowchart TD U14["U14 MCP2518FD CAN Controller"] -->|TXCAN RXCAN| IC3["IC3 ISOW1044 Isolated CAN Transceiver"] IC3 --..."
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