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Integration limits
PCB thermal limits, TIM resistance, connector ampacity, and creepage clearances are checked against standard mechanical integration.
Check whether a bare 100A board-level servo drive fits your current envelope and thermal interface before locking the mechanical housing for your robotic joint.
Published July 19, 2026; evidence and assumptions reviewed July 19, 2026. The calculator is a screening tool; final release still requires mechanical CAD integration and thermal prototype validation.
Screen current envelope, pulse duration, and PCB thermal integration limits before selecting a bare 100A board for your actuator.
Phase RMS current; check PCB thermal limits.
Must be equal to or higher than continuous current.
Board-level trace heating limits long pulses.
Integration heavily dictates continuous current rating.
Enter Arms continuous current
Enter Arms peak current and pulse duration
Enter pulse duration and cooling method
PCB thermal limits, TIM resistance, connector ampacity, and creepage clearances are checked against standard mechanical integration.
Calculator screens bare board, thermal pad to chassis, and active cold plate scenarios.
The supplier check lists mounting torque, standoff height, TIM thickness, and pin ratings.
Passing 100A through a compact PCB usually requires a documented IPC-2152 current-carrying calculation, heavy copper, parallel planes, busbar reinforcement, or equivalent high-current construction. Standard 2oz layouts must not be assumed safe at this current.
Unlike enclosed drives, a board-level drive relies on your housing for heat flow. You must use the supplier-specified TIM thickness, compression, pressure range, and heat-sink surface finish.
GaN FETs can reduce switching loss in compact power stages, but layout, gate drive, shielding, and conduction losses still determine whether a bare-board 100A design is realistic.
The calculator focuses heavily on the thermal interface method. A 100A bare board cannot dissipate high continuous current without pad-to-chassis or cold-plate integration.
| Input | Why it matters | Screening rule |
|---|---|---|
| Continuous current | Sets average heat load in the PCB planes and power FETs. Determines if TIM is strictly required. | If it exceeds the thermal interface ceiling, you must upgrade the cooling method or derate. |
| Peak current | Checks whether torque bursts fit the 100A silicon and trace envelope without causing delamination. | Any value above 100A is unsafe for standard board-level traces unless busbars are used. |
| Peak duration | Separates a microsecond switching pulse from a thermal event that heats the copper planes. | Longer pulses require a dedicated cold plate to pull heat away from the PCB quickly. |
| Thermal Interface | A bare PCB in still air will overheat at a fraction of the current that a cold-plated board can handle. | Pad or cold-plate selection drastically changes the continuous current rating. |
The page separates general engineering rules for PCB ampacity from vendor-specific ratings. IPC standards support the copper thickness realities, but supplier datasheets must confirm the exact connector and TIM requirements.
Review cycle: refreshed every six months, or sooner when thermal interface materials or PCB manufacturing standards change.
| Source | Supports | Boundary | Date note |
|---|---|---|---|
| IPC-2152 Standard for Determining Current Carrying Capacity in Printed Board Design | Trace width, copper thickness, board construction, and temperature rise dictate how much continuous current a bare board can carry. | Follow IPC current-carrying calculations for copper weight, plane geometry, temperature rise, and cooling context; do not assume all 100A FETs imply a 100A board assembly. | IPC source reviewed July 19, 2026 |
| Henkel thermal gap pad material guidance | Effective heat transfer from the board to the robot chassis requires specified TIM thickness, W/m·K rating, compression, and uniform mounting force. | Thermal pad compression, pressure, and thickness are supplier-specific. Treat 30-50% compression as an example range only when it appears in the selected TIM datasheet or application note. | General TIM guidelines reviewed July 19, 2026 |
| Amphenol RADSOK PGY high-current connector data | A board cannot output 100A continuously if the phase connectors, terminals, or solder joints are rated below the required current after derating. | Pins and headers are often the bottleneck before the FETs. Verify the connector datasheet for continuous ampacity, temperature rise, contact resistance, and PCB termination method. | Connector rating source reviewed July 19, 2026 |
| Texas Instruments GaN motor-drive guidance | Wide-bandgap GaN devices can reduce switching loss and support high-frequency compact power stages. | GaN benefits depend on layout and gate drive; fast switching edges can increase EMI exposure if the board, cable, and housing are not designed as one system. | TI source reviewed July 19, 2026 |
If your result is a boundary case, package the duty cycle, thermal interface plan, and mounting CAD before asking for a written supplier rating.
Send integration specsPushing 100A through a board fundamentally changes the PCB stackup, connector height, and mechanical mounting strategy compared to a lower-current board.
| Parameter | 40A to 60A boards | 100A boards | Decision impact |
|---|---|---|---|
| PCB Construction | Standard 2oz copper, standard stackup | Heavy copper (4oz+/140µm), embedded busbars, or metal-core | A 100A board needs heavy copper or busbars, making the PCB thicker and more expensive to manufacture, pushing trace widths beyond standard envelopes. |
| Phase Connectors | Low-profile headers or direct solder (40A) | High-current press-fit, soldered busbar, multi-contact, or equivalent datasheet-rated interface | Large terminals, press-fit contacts, or busbar interfaces can increase Z-height and assembly complexity. Verify the derated current and temperature rise for the exact connector family. |
| Thermal Integration | Forgiving thermal tolerances | Strict flatness, torque, TIM compression, and heat-spreader requirements | A 100A board requires supplier-defined TIM thickness, compression, mounting torque, and flatness to couple heat to your housing without board stress. |
| DC Bus Capacitance | Smaller capacitors fit easily | Requires external capacitor bank or active braking | Regeneration can quickly over-voltage a compact board that lacks space for large bulk capacitors. |
| Integration Cost | Lower BOM and simpler housing design | Higher PCB, specialized connector, and heat-sink cost | Use the smaller class when 100A is only a vague safety margin, as board-level integration costs scale sharply with current. |
| Tool result | Typical condition | Required action |
|---|---|---|
| Candidate fit | Continuous current is moderate, peak is below 100A, using a chassis thermal pad. | Proceed to supplier quotation; verify TIM thickness and mounting hole locations. |
| Boundary case | Peak is near 100A, duration is several seconds, or relying on bare board cooling. | Request thermal simulation, heavy copper details, and custom I2t limits. |
| Outside envelope | Continuous current or peak current exceeds 100A. | Move to a larger enclosed drive or a custom multi-board power stage. |
| Likely oversized | Continuous current is low and peak current stays below about 50A. | Evaluate 40A to 60A boards to save space, reduce Z-height, and lower cost. |
The highest-impact mistakes for bare boards are usually poor TIM contact, under-rated connectors, and unprotected EMI, rather than just the silicon FET rating.
| Risk | Trigger | Mitigation |
|---|---|---|
| Thermal runaway due to poor TIM contact | Uneven mounting pressure or warped chassis surface | Specify thermal pad conductivity, thickness, and mounting screw torque in your assembly SOP. |
| Connector melting | Pushing 100A through standard headers designed for 40A | Review connector datasheets and use direct-solder joints or high-ampacity terminals for phase outputs. |
| Regeneration over-voltage on a small board | High deceleration energy with no space for large capacitors on the PCB | Allocate space for external bulk capacitors or a braking resistor module near the drive. |
| Unshielded EMI | High-frequency GaN switching on a bare board inside a non-metallic joint | Ensure the housing provides an EMI shield and motor cables are kept extremely short. |
| Question | Why it matters |
|---|---|
| What is the required thermal interface material (TIM) thickness, W/m·K rating, and target compression percentage? | If you use a different TIM or miss the supplier-specified compression and pressure range, the board can overheat even when the current inputs appear acceptable. |
| What is the continuous current rating of the phase output connectors or pins? | The silicon might handle 100A, but the connector, solder joint, or press-fit terminal may be the first derating limit. Ask for the exact connector datasheet and test condition. |
| Are there mounting torque or clamping-force specifications to prevent PCB warping? | Clamping the board too tightly can crack components or bow the PCB; clamping too loosely causes thermal failure and high contact resistance. |
| How much external capacitance is required for my expected braking energy? | Compact boards almost never have enough onboard capacitance to handle heavy robot deceleration. |
| Does the board use 4oz+ heavy copper or embedded busbars? | Standard 2oz copper cannot be assumed to carry 100A safely. Ask for the supplier current-carrying calculation, copper stackup, and measured temperature-rise data. |
| Case | Input assumption | Outcome |
|---|---|---|
| AGV drive wheel integration | 45A continuous, 90A peak, 2s pulse, thermal pad to chassis | Candidate fit, but verify connector ampacity and TIM compression. |
| Compact surgical robot arm | 15A continuous, 35A peak, 1s pulse, bare board | Likely oversized; evaluate 40A board-level drives to save critical space. |
| Direct-drive exoskeleton joint | 85A continuous, 100A peak, 5s pulse, active cold plate | Boundary case; proceed only with rigorous thermal simulation and heavy copper verification. |
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