RS-TMP6331-100K — Precision Silicon PTC Temperature Sensor Module

Precision Temperature Sensing with Built-In Safety

The RS-TMP6331-100K is a high-linearity silicon PTC temperature sensor module designed for engineers who need reliable, repeatable thermal measurements without the headaches of traditional NTC thermistors. Built on the genuine Texas Instruments TMP6331 with a 100kΩ ±0.5% precision metal film bias resistor — paired with a 150 °C-rated filter capacitor — this module delivers predictable, linear resistance output that eliminates the exponential math and large lookup tables that NTC sensors demand.

The high-impedance 100kΩ architecture draws only 16.5µA at 3.3V — making it ideal for battery-powered IoT, remote monitoring, and energy-harvesting applications where every microamp counts.

Key Specifications

Sensor IC	Texas Instruments TMP6331 Silicon Linear PTC (genuine)
Sensing Range	-40°C to +150°C
Supply Voltage	1.8V to 5.5V
Nominal Resistance (R₂₅)	100,000Ω ±1%
Bias Resistor	100,000Ω ±0.5% precision metal film
Passive Temp Rating	150 °C-rated bias resistor & filter capacitor
Temperature Coefficient	+6,400 ppm/°C
Sensing Current @ 3.3V	16.5 µA
Max Bias Current	100 µA
Power Dissipation	<0.25 mW
Output Type	Ratiometric — resistance-based via voltage divider (connect to ADC)
PCB Material	Aluminum MCPCB (1.0–3.0 W/m·K)
Module Dimensions	20 mm × 9 mm
Mounting	M3 screw hole (3.2mm) for secure thermal contact
Pinout	Pin 1: 5V (Vbias) · Pin 2: Gnd · Pin 3: o (analog output to ADC)
Max Continuous Operation	125°C
Peak Exposure	150°C (intermittent)
Storage Temperature	-65°C to +150°C

Why Silicon PTC Beats NTC

Parameter	Standard NTC	RS-TMP6331-100K (Silicon PTC)
Linearity	Exponential — complex Steinhart-Hart math	Linear — predictable output, simple polynomial
Tolerance	1–5% (hobbyist grade)	0.5% precision metal film bias resistor
Thermal Safety	NTC resistance drops with heat — thermal runaway risk	PTC resistance increases with heat — self-limiting, inherently safer
Interchangeability	Low — each unit varies significantly	High — consistent unit-to-unit from factory
Software Complexity	Large lookup tables, Steinhart-Hart equation	Simple ratiometric formula, small LUT
Self-Heating Stability	NTC gets worse at higher voltage — resistance drops, current increases	PTC self-limits — resistance increases with heat, current decreases

Ratiometric Measurement — Supply-Independent Accuracy

The RS-TMP6331-100K uses a ratiometric configuration where the ADC reference voltage is the same supply that biases the sensor. This mathematically cancels supply voltage drift — whether you’re running from a stable 3.3V LDO or a sagging battery, the temperature reading stays accurate.

Formula (use raw ADC counts, not voltage):

R_thermistor = 100,000 × (ADC_max − ADC_count) ÷ ADC_count

Where ADC_max = 1024 (10-bit) or 4096 (12-bit). Then map resistance to temperature using the provided lookup table.

Built-In Fault Diagnostics

ADC Value (10-bit)	Interpretation	Meaning
0 to 5	SHORT CIRCUIT	Sensor or signal line shorted to ground
10 to 900	NORMAL	Sensor operating within valid range
1020 to 1023	OPEN CIRCUIT	Sensor disconnected or wire broken

Professional firmware should implement these fault checks before trusting any temperature reading — the datasheet includes production-ready Arduino code with fault diagnostics built in.

Ideal Applications

• Industrial motor & transformer monitoring — M3 screw mount provides secure thermal contact on casings
• Battery pack thermal management (BMS) — 16.5µA sensing current preserves battery life
• 3D printer thermal protection — aluminum MCPCB responds 2× faster than FR4
• Relay thermal control loops — built-in Schottky diode enables direct inductive load interfacing
• Automotive temperature sensing — -40°C to +150°C range covers full automotive spec
• IoT remote monitoring — ultra-low power, ratiometric measurement tolerates battery voltage sag
• Arduino & ESP32 projects — sample code included, connect to any analog pin

Arduino Sample Code Included

The datasheet includes production-ready Arduino code with 10-sample averaging filter, ratiometric resistance calculation, lookup table interpolation, and fault diagnostics. Copy, paste, upload — temperature readings in under 5 minutes.

Related Modules

Prefer an analog voltage output (10 mV/°C) instead of ratiometric resistance? See the SwiftSense T235 (±0.5 °C, TI TMP235). See the measured benefit of aluminum in our Aluminum PCB vs FR4 thermal response test, or browse all Ramanu sensor modules.

Designed & Made in India

Engineered and assembled by Ramanu Systems, Pune, Maharashtra. Genuine TI TMP6331 from authorized distribution, with a ±0.5% precision bias resistor and 150 °C-rated passives so the whole module — not just the sensor — survives the full temperature range. Every module tested before dispatch.