Public evidence

electrical.thermal.heatsink_rth

Machine-checked verification for calculation version 1.1.0 · tier internally_reviewed

Open calculator API Capability Download JSON CVP Manifest MCP Review policy

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· Lumped steady-state Rθ; not Zth(t), CFD, or θCA+θSA (double-count) · Protocol · Schema · Production report

Declared partition coverage: PASS · 4/4 declared partitions (ja, stack, required-sa, invalid-domain)
Versions: Calculation 1.1.0 · CVP protocol 1.0.0-proposed
CVP identity: 3/3 property · digest e84796291008

Verification

Legacy regression suite: 17/17 calculation tests · Production surface contract 4/4

Three distinct suites: educational examples on the calculator page, this legacy regression count (17/17 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.1.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Calculation version 1.1.0. CVP 1.0.0-proposed. 4/4 golden · 8/8 CVP boundary · 9/9 invalid · 3/3 property · 3/3 metamorphic · 2/2 round-trip · 3/3 cross-interface · 1/1 cross-calculator · 4/4 CVP contract. digest e84796291008.

Golden (oracle-backed) 4 / 4
CVP boundary 8 / 8
Invalid input 9 / 9
Property 3 / 3
Metamorphic 3 / 3
Round-trip 2 / 2
Cross-interface 3 / 3
Cross-calculator 1 / 1
CVP contract 4 / 4
Interfaces PASS · UI (SSR) / REST / MCP
Interface claim ui-ssr is query-result HTML, not a live browser session.
Assurance Engineering

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:4e5f89c5bbd8f444c91daa988c9085b4d4e159aff60af497e4dd5e180c4ce60a

Input schema sha256:e0368bf8a72142969285ce1e69ef710a5a43f00276ab16322c9e8cfc0061058d · Output schema sha256:ba3caefa631d7ec1c7571e9d97c0ffb097099dcfed5105f8dc46fb4d5086cc26 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: heatsink-rth
Engine: heatsink-rth
Engine build: 2026-09-13
Evidence core: 2026-09-13T22:54:03.327Z
Rendered: 2026-09-16T22:03:43.744Z
Last reviewed: 2026-09-14

Assumptions

Steady-state lumped thermal resistance
Rθ constant (not Zth(t))
θJA is an effective / application value, not a JEDEC-board package constant
θJC+θCS+θSA is a single series path; parallel PCB/package paths are ignored
P is device dissipation converted to heat

Limitations

Steady-state lumped Rθ only; not Zth(t) or CFD
θJA and θJC+θCS+θSA are exclusive models — mixing them is CONFLICTING_INPUTS
Required mode reports θSA,max, not total θJA
θCA / Rth_HS are rejected: θCA already includes the ambient-side path
Parallel PCB/package heat-flow paths are ignored on the explicit stack
P is device dissipation converted to heat, not load or output power
θSA,max ≤ 0 returns HEATSINK_INFEASIBLE and is not a purchasable heatsink

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

JEDEC JESD51 series — Integrated Circuits Thermal Measurement Method — Junction-to-ambient and junction-to-case thermal metrics on specified test boards
Supports: Tj = Ta + P·θJA as a thermal-metric estimate; θJA is test-condition specific
Analog Devices — Practical Design Techniques for Power and Thermal Management — Section 8, Fig. 8.50 — junction → case → case-to-sink → sink-to-ambient
Supports: θJA = θJC + θCS + θSA; required θSA,max = (Tj,max−Ta)/P − θJC − θCS
Texas Instruments SPRA953 — Semiconductor and IC Package Thermal Metrics — RθJA, RθJC, and application dependence of junction-to-ambient metrics
Supports: θJA is not a universal equivalent of the explicit case/heatsink stack
Analog Devices — Thermal Characterization of IC Packages — θCA is case-to-ambient (all case-to-ambient paths); θJA = θJC + θCA
Supports: Do not add θCA to θSA — θCA already includes the ambient-side path

Legacy published checks

Golden and boundary cases from the legacy Evidence JSON. CVP property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the Manifest — including SKIP when a suite has no vectors.

ID	Kind	Status	Detail
`rise`	golden	pass	Expected Tj_C=35 · dT_C=10 · thermal_path=JA · Actual Rth_JA=5 · Rth_total=5 · Tj_C=35 · mode=junction_effective_ja · thermal_path=JA · Ta_C=25 · P_W=2 · Rth_C_per_W=5
`stack`	golden	pass	Expected Tj_C=35 · Rth_total=5 · thermal_path=JC+CS+SA · Actual Rth_JC=1.5 · Rth_CS=0.5 · Rth_SA=3 · Rth_total=5 · dT_JC_C=3 · dT_CS_C=1 · dT_SA_C=6 · Tj_C=35
`required-sa`	golden	pass	Expected Rth_SA_required=10.5 · Rth_total_max=12.5 · thermal_path=required_SA · Actual Rth_JC=1.5 · Rth_CS=0.5 · Rth_total_max=12.5 · Rth_SA_required=10.5 · Tj_max_C=150 · mode=required_heatsink_sa · thermal_path=required_SA · Ta_C=25
`zero-P-rise`	golden	pass	Expected Tj_C=25 · dT_C=0 · Actual Rth_JA=5 · Rth_total=5 · Tj_C=25 · mode=junction_effective_ja · thermal_path=JA · Ta_C=25 · P_W=0 · Rth_C_per_W=5
`legacy-ca`	boundary	pass	Expected CONFLICTING_INPUTS · Actual CONFLICTING_INPUTS
`missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-required-p-zero`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-infeasible`	boundary	pass	warning HEATSINK_INFEASIBLE
`boundary-legacy-hs`	boundary	pass	Expected CONFLICTING_INPUTS · Actual CONFLICTING_INPUTS
`property-dT-identity`	property	pass	ΔT=P·θJA
`property-zero-power`	property	pass	P=0 → Tj=Ta
`property-ambient-shift`	property	pass	Tj(Ta+c)=Tj(Ta)+c
`property-power-mono`	property	pass	P↑ → Tj not lower
`property-rth-mono`	property	pass	θ↑ → Tj not lower
`property-stack-sum`	property	pass	θtotal=θJC+θCS+θSA
`property-required-sa`	property	pass	θSA,max=10.5
`property-sa-roundtrip`	property	pass	plug θSA,max → Tj,max