check_design_fit

Validate whether a component will work within your operating conditions. Compares your design parameters against the datasheet's absolute maximum ratings and recommended operating conditions. Returns PASS/FAIL/WARNING per parameter with margin percentages.

Parameter mapping by component type:

• Buck/boost converters: input_voltage, output_voltage, output_current, ambient_temp

• MOSFETs: supply_voltage=VDS, output_current=ID (drain current), ambient_temp

• LDOs: input_voltage, output_voltage, output_current, ambient_temp

• Logic ICs: supply_voltage=VCC, ambient_temp

Result semantics (per-parameter 'result' field):

• PASS: comfortable margin. For a recommended-operating RANGE, any value inside the range (including the exact edges) is PASS. For an absolute-MAX rating, PASS means more than 10% below the limit.

• WARNING: for absolute-max ratings only, the user value is within 10% of the limit (but not over) — part will work but with thin margin for part-to-part variation, temperature drift, and transients. Consider derating.

• FAIL: user value is outside the allowed range / exceeds the limit — part is out of spec and will be stressed or damaged.

• INSUFFICIENT_DATA: the check could not be completed safely — most commonly an ambient_temp input that could not be translated to a junction-temperature check (see the temperature note below). INSUFFICIENT_DATA never counts as a PASS: it pulls the overall verdict down to at-least-WARNING. Each check also reports 'limit_type' (max / min / range / fixed) so you can see whether it was judged against an operating range, an absolute-max rating, or a fixed-output setpoint. Checks read from the datasheet text (source='llm') also carry 'source_quote', the datasheet row the limit was taken from. A condition with no limit anywhere is listed in 'unmatched' and keeps the overall verdict at WARNING; a clean PASS means every condition was checked.

Temperature honesty:

• ambient_temp is NOT silently treated as a junction temperature. The stored operating-temperature limit is junction-suspect, so a bare ambient input is never reported as a clean PASS on thermal grounds. If you also supply input_voltage, output_voltage and output_current AND a thermal-resistance (RthJA) value is available, the tool estimates Tj = Ta + Pd·RthJA (Pd ≈ (Vin-Vout)·Iout, a documented approximation) and checks the junction estimate — reported as 'temperature (junction est.)' with the assumptions in the note. Otherwise the temperature check returns INSUFFICIENT_DATA asking you to pull RthJA via read_datasheet. The 'temperature_basis' field (junction / ambient / unknown) tells you which basis was used.

Behavior:

• Two-tier validation. For parameters in our structured database (Vin, Iout, operating temp, etc.), returns instantly and free of LLM cost. For parameters only found in the datasheet text, falls back to an LLM read of the absolute-max and recommended-operating-conditions sections. The 'validation_method' field in the response tells you which path was used.

• If the part hasn't been extracted yet and the LLM fallback is needed, this call triggers extraction (30s-2min). Returns status='extracting' if so — poll check_extraction_status and retry.

When NOT to use:

• You need power dissipation or junction-temperature rise — this tool only checks nameplate limits. Pull RthJA from read_datasheet and calculate yourself.

• You need SOA (safe-operating-area) curve checks for MOSFETs — use analyze_image on the SOA graph.

• You're checking a passive or mechanical part with no abs-max table — there's nothing for this tool to compare against.

Example: check_design_fit('TPS54302', input_voltage=24, output_current=2.5, ambient_temp=70)