Check Design Fit
check_design_fitCosts 5¢ per call. Checks your operating conditions against the part's absolute maximum ratings and recommended operating conditions; returns PASS / WARNING / FAIL / INSUFFICIENT_DATA per condition and overall. Conditions by part type: converters and LDOs take input_voltage, output_voltage, output_current, ambient_temp, efficiency; MOSFETs take supply_voltage (VDS), output_current (ID), ambient_temp, power_dissipation; logic ICs take supply_voltage (VCC). Verdicts:
PASS: inside the recommended range, or at or below the derated limit. By default input_voltage and supply_voltage must stay at or below 80% of the absolute-maximum rating when no recommended maximum is known (inside a recommended range is a PASS), and output_current at or below 80% of its tightest rating; derating_pct changes this. Zero headroom on a rated current always warns. This is a screening policy; derating_reference cites the reliability guidance and its limits. Each check reports margin_pct against the raw limit, derating_pct and derated_limit.
WARNING: within the limit but above the derated limit, above the recommended maximum but below the absolute maximum, or within 10% of an absolute maximum that isn't derated.
FAIL: outside the range or over the limit.
INSUFFICIENT_DATA: not safely checkable, usually an ambient_temp that could not be turned into a junction-temperature check. It never counts as a PASS. Each check has limit_type (max / min / range / fixed); checks read from the datasheet text (source='llm') carry source_quote, the row the limit came from. A condition with no limit is listed in unmatched and holds the overall verdict at WARNING. If the ratings came from a different MPN than you asked for, resolved_as and data_quality_warning lead the response. Temperature: ambient_temp is never silently compared with a junction limit. When the part's own dissipation is known, the tool estimates Tj = Ta + Pd × RθJA (RθJA from the datasheet's thermal table) and judges Tj against the junction limits, reported as 'temperature (junction est.)'. Pd by part type: LDO (Vin - Vout) × Iout; switching converter Vout × Iout × (1/η - 1), which needs efficiency; anything else, pass power_dissipation (for a MOSFET, ID² × RDS(on)). Without these the check is INSUFFICIENT_DATA and its note says what to pass. Current ratings are read at ambient_temp (a MOSFET's 25 °C drain current is derated towards its maximum junction temperature). temperature_basis says which basis was used. Stored parameters answer instantly; anything else is read from the datasheet's ratings tables (validation_method says which). A part not yet extracted starts extraction and returns status='extracting' (not charged). A new datasheet takes about 2.5 minutes at the median and 6.5 minutes at the 90th percentile; a cold GPU start can take about 12 minutes. These are estimates, not deadlines. Not for: transient or full thermal analysis (the junction estimate is a steady-state screen), MOSFET SOA curves (analyze_image the SOA graph), passives with no ratings table. Example: check_design_fit('TPS54302', input_voltage=24, output_voltage=5, output_current=2.5, ambient_temp=70, efficiency=0.92)
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| efficiency | No | Converter efficiency at this operating point, as a fraction (0.92) or a percentage (92). Lets the tool estimate a switching converter's junction temperature. | |
| part_number | Yes | Specific manufacturer part number (MPN) or LCSC number (e.g. 'TPS54302DDCR', 'C2837938'). Not a value ('100nF'), description or reference designator ('R1'). | |
| ambient_temp | No | Ambient temperature TA (°C). | |
| derating_pct | No | Percent below a rating a PASS must stay, for input_voltage, supply_voltage and output_current. Default 20 (run at no more than 80% of the rating). 0 turns optional derating off; no current headroom still warns. | |
| input_voltage | No | Input voltage / VIN (V). For converters. | |
| output_current | No | Output current / IOUT (A). For MOSFETs, this is drain current ID. | |
| output_voltage | No | Output voltage / VOUT (V). For converters/LDOs. | |
| supply_voltage | No | Supply voltage / VCC / VDD (V). For MOSFETs, VDS; compared against VDS(max) only. | |
| power_dissipation | No | The part's own power dissipation (W), if you have worked it out (e.g. ID² × RDS(on) for a MOSFET). Used for the junction-temperature estimate. | |
| switching_frequency | No | Switching frequency FSW (kHz). For converters. |