Texas Instruments TMP6331DECT

Overview

TMP6331DECT from Texas Instruments is a silicon-based linear positive temperature coefficient (PTC) thermistor in a 0402-compatible X1SON package, delivering ±1% R25 tolerance at 25 °C (100 kΩ), 6400 ppm/°C TCR at 25 °C, and operation from –40 °C to +125 °C for the DEC variant-used in precision thermal monitoring of motor windings, power converters, and display backlight circuits.

For engineers reviewing the TMP6331DECT datasheet, TMP6331DECT pinout, TMP6331DECT application, or TMP6331DECT equivalent, key selection considerations include its linear resistance vs. temperature behavior, built-in fail-safe response during overtemperature events, low self-heating due to 40 µA max bias current, and compatibility with ratiometric ADC interfaces using voltage-divider or current-source biasing.

Technical Context

The TMP6331DECT operates as a two-terminal passive resistive sensor with polarity-sensitive terminals (+ and –), requiring positive bias where the + terminal is at higher potential. Its resistance varies linearly with temperature across –40 °C to +125 °C, eliminating need for external linearization circuitry or multi-point calibration typically required by NTC thermistors.

It exhibits consistent sensitivity (±0.2% TCR tolerance) and fast thermal response (0.6 s in stirred liquid), enabled by low thermal mass and silicon process control of doping and active area. Self-heating is minimized by limiting bias current to ≤40 µA and voltage to ≤5.5 V, with junction-to-ambient thermal resistance of 443.4 °C/W in the DEC package.

Key Specifications

Pinout & Package

The TMP6331DECT is housed in a 2-pin X1SON package (0.60 mm × 1.00 mm), footprint-compatible with standard 0402 (inch) land patterns. It features exposed pad thermal path and polarity-marked terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear thermistor applications.

Compared with TMP6331DECT, TMP6331DYCT extends temperature range and thermal robustness at the cost of slower response and larger footprint, while TMP6131DECT trades R25 value for improved drive capability in noisy environments-neither is pin-compatible but both share identical biasing topology and firmware interface logic.

Availability

TMP6331DECT is available at Aetrix Electronics and suitable for industrial motor control, display backlight compensation, and battery charger thermal safety applications requiring stable component supply, traceable lot data, and lifecycle continuity support.

Supply support for TMP6331DECT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and connectivity technologies, with leadership in precision sensing and power management solutions.

The TMP63 series is part of TI's linear thermistor product line, designed specifically to replace NTCs in high-accuracy, low-maintenance thermal sensing applications across industrial, automotive, and consumer systems.

FAQ

What is the maximum operating temperature for the TMP6331DECT?

The TMP6331DECT is rated for continuous operation from –40 °C to +125 °C in its X1SON (DEC) package. This limit is defined by its junction temperature specification and thermal resistance (RθJA = 443.4 °C/W). Exceeding 125 °C risks accelerated long-term drift and violates recommended operating conditions-use TMP6331DYCT for +150 °C applications. The TMP6331DECT datasheet specifies absolute maximum junction temperature as 155 °C, but sustained operation above 125 °C is not supported.

Does the TMP6331DECT require external linearization circuitry?

No, the TMP6331DECT does not require external linearization circuitry. Its silicon-based PTC structure delivers a highly linear resistance vs. temperature curve across –40 °C to +125 °C, with TCR variation of only ±0.2% over that range. This eliminates the need for parallel compensation resistors or complex NTC polynomial fitting-enabling direct use with simple voltage-divider or current-source biasing and straightforward firmware conversion using TI's Thermistor Design Tool.

How does the built-in fail-safe behavior of the TMP6331DECT work?

The TMP6331DECT's built-in fail-safe behavior relies on its positive temperature coefficient: during a short-to-supply event, increased current causes self-heating, which raises resistance and inherently limits further current flow-preventing thermal runaway. In contrast, an NTC would decrease resistance under the same condition, creating destructive positive feedback. This passive protection is intrinsic to the TMP6331DECT's material properties and requires no additional components.

Can the TMP6331DECT be used with a ratiometric ADC configuration?

Yes, the TMP6331DECT is optimized for ratiometric ADC use. When biased with the same voltage (VBIAS) applied to the ADC's reference input, supply tolerance errors cancel out-improving absolute accuracy without precision voltage references. Equation 4 in the TMP6331DECT datasheet confirms this cancellation mathematically. This configuration is especially effective with 12-bit or higher ADCs and reduces system-level calibration burden.

What is the thermal response time of the TMP6331DECT, and how is it measured?

The TMP6331DECT has a thermal response time of 0.6 seconds to reach 63% of final resistance value when transitioning from 25 °C to 125 °C in stirred liquid, per JEDEC JESD51-13. This metric reflects its low thermal mass and small 0.60 mm × 1.00 mm X1SON footprint. In still air, response slows to 3.2 s (25 °C to 70 °C), confirming its suitability for dynamic thermal event detection in compact, high-power-density layouts.