MAX31865 RTD-to-Digital Converter

@@ -0,0 +1,66 @@+# MAX31865++**Analog Devices** · RTD Interface · TSSOP-20++The MAX31865 is a resistance-to-digital converter optimized for platinum RTDs (PT100 and PT1000). It digitizes the RTD resistance with a 15-bit ADC and reports it over SPI, handling the reference-resistor ratiometric measurement, 2/3/4-wire configurations, and fault detection (open, short, overvoltage). It gives precise, low-drift temperature measurement for industrial sensing.++## Pinout++| Pin | Name | Type | Function |+|---|---|---|---|+| 1 | DRDY | output | Active-low, push-pull data-ready output. DRDY goes low when a new conversion result is available in the RTD data register; it returns high after that register is read. |+| 2 | DVDD | power_in | Digital supply voltage input, 3.0V-3.6V (nominally 3.3V). Bypass to DGND with a 0.1µF capacitor. |+| 3 | VDD | power_in | Analog supply voltage input, 3.0V-3.6V (nominally 3.3V). Bypass to GND1 with a 0.1µF capacitor. |+| 4 | BIAS | output | Bias voltage output (VBIAS ≈ 2.0V). Provides the bias for the reference and RTD networks; drives up to 5.75mA. |+| 5 | REFIN+ | input | Positive reference-voltage input. Connect to BIAS. Reference resistor (RREF, 350Ω-10kΩ) is placed between REFIN+ and REFIN-. |+| 6 | REFIN- | input | Negative reference-voltage input. Reference resistor is connected between REFIN+ and REFIN-. |+| 7 | ISENSOR | passive | Low side of RREF; connect to REFIN-. Carries the RTD bias current returning through the reference resistor. |+| 8 | FORCE+ | output | High-side RTD drive. Connect to FORCE2 when using the 3-wire connection configuration. Protected to ±45V. |+| 9 | FORCE2 | bidirectional | Positive input used in 3-wire configuration only. Tie to FORCE+ for 3-wire RTDs; ground for 2-wire and 4-wire configurations. Protected to ±45V. |+| 10 | RTDIN+ | input | Positive RTD sense input. Protected to ±45V. |+| 11 | RTDIN- | input | Negative RTD sense input. Protected to ±45V. |+| 12 | FORCE- | passive | Low-side RTD return. Protected to ±45V. |+| 13 | GND2 | power_in | Analog ground. Connect to GND1. |+| 14 | SDI | input | SPI serial-data input (MOSI). Sampled on the rising edge of SCLK. |+| 15 | SCLK | input | SPI serial-data clock input. |+| 16 | CS | input | Active-low chip select. Drive CS low to enable the SPI interface. |+| 17 | SDO | output | SPI serial-data output (MISO). |+| 18 | DGND | power_in | Digital ground. |+| 19 | GND1 | power_in | Analog ground. Connect to GND2. |+| 20 | N.C. | unconnected | No internal connection. Do not connect. |++## Key specifications++| Parameter | Value |+|---|---|+| Type | RTD-to-digital converter |+| Sensors | PT100 / PT1000 (2/3/4-wire) |+| ADC | 15-bit |+| Accuracy | 0.5% of full scale (max) |+| Interface | SPI |+| Fault detection | Open, short, overvoltage |+| Supply voltage | 3.0 V to 3.6 V |+| Operating temperature | -40 C to 85 C |++## Ordering variants++- `MAX31865AAP+`+- `MAX31865AAP+T`+- `MAX31865ATP+`+- `MAX31865ATP+T`++## CAD (KiCad official)++- Symbol: `max31865.kicad_sym`+- Footprint: `max31865.kicad_mod`+- 3D model: TSSOP-20 body from KiCad `Package_SO/TSSOP-20_4.4x6.5mm_P0.65mm`.++## Provenance++Data extracted from the manufacturer datasheet, not a distributor listing:++- **Datasheet:** [Analog Devices datasheet](https://www.analog.com/media/en/technical-documentation/data-sheets/MAX31865.pdf) (26 pp, sha256 `88f540410eb8c2ac`, retrieved 2026-08-17, tier: manufacturer)+- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.+- **CAD:** KiCad official libraries (CC-BY-SA 4.0).++[Datasheet PDF](docs/max31865-datasheet.pdf)

@@ -0,0 +1,37 @@+{+  "slug": "max31865",+  "version": "0.1.0",+  "type": "component",+  "description": "Resistance-to-digital converter for PT100/PT1000 RTD temperature sensors, SPI.",+  "tags": [+    "rtd",+    "pt100",+    "pt1000",+    "temperature",+    "spi",+    "adi",+    "tssop-20"+  ],+  "dependencies": {},+  "hero": {+    "type": "image",+    "path": "docs/hero.png"+  },+  "files": [+    "page.json",+    "README.md",+    "max31865.kicad_sym",+    "max31865.kicad_mod",+    "max31865.glb",+    "max31865.step",+    "docs/hero.png",+    "docs/max31865-datasheet.pdf",+    "viewers/symbol.html",+    "viewers/footprint.html"+  ],+  "visibility": "public",+  "author": {+    "name": "Ray",+    "email": "[email protected]"+  }+}\ No newline at end of file