Texas Instruments TMP6431DECT

Overview

TMP6431DECT from Texas Instruments is a silicon-based linear positive temperature coefficient (PTC) thermistor with 47-kΩ nominal resistance at 25 °C (±1% tolerance over 0 °C to 70 °C), 6400 ppm/°C TCR at 25 °C, and –40 °C to +150 °C operating range in a 0402-compatible X1SON package. It delivers fast thermal response (0.6 s in stirred liquid) and built-in fail-safe behavior during short-circuit events, enabling precise temperature monitoring in space-constrained motor control and charger systems.

For engineers reviewing the TMP6431DECT datasheet, TMP6431DECT pinout, TMP6431DECT application, or TMP6431DECT equivalent, key selection considerations include its linear R–T curve eliminating NTC linearization circuitry, ±0.2% typical TCR tolerance across temperature, 100 µA max bias current compliance, and compatibility with ratiometric ADC interfaces using 47-kΩ bias resistors.

Technical Context

The TMP6431DECT operates as a two-terminal voltage-biased PTC sensor whose resistance increases linearly with temperature-enabling direct polynomial or lookup-table conversion without external linearization components. Its silicon process ensures consistent TCR (6400 ppm/°C at 25 °C) and low long-term drift (0.5% typical after 600 h at 150 °C).

It requires unidirectional biasing: pin 2 (+) must be held at higher potential than pin 1 (–) to maintain proper junction polarization. Self-heating is minimized by low thermal mass and operation within 0–100 µA bias current, with dissipation effects quantified via R_θJA = 443.4 °C/W (X1SON).

Key Specifications

Pinout & Package

TMP6431DECT uses a 2-pin X1SON package (0.60 mm × 1.00 mm), footprint-compatible with industry-standard 0402 (inch) land patterns. The device has no internal circuitry-only passive thermistor terminals requiring correct polarity for reliable operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TMP6431DECT, TMP6431DCKT offers superior thermal dissipation in high-power environments but requires PCB redesign, while TMP6131DECT maintains identical form factor and linearity at 10 kΩ-making it ideal for low-voltage, low-power thermal sensing where 47 kΩ would exceed ADC input impedance limits.

Availability

TMP6431DECT is available at Aetrix Electronics and suitable for motor control thermal protection, USB-C charger temperature monitoring, and HVAC thermostat sensing requiring stable component supply across extended temperature ranges and high-reliability production cycles.

Supply support for TMP6431DECT 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 and embedded processing technologies, with leadership in precision sensing, power management, and signal chain solutions.

The TMP64 series is part of TI's linear thermistor portfolio designed specifically to replace NTCs in high-accuracy, low-maintenance temperature sensing applications-emphasizing linearity, long-term stability, and fail-safe behavior in industrial and automotive systems.

FAQ

What is the maximum operating temperature for TMP6431DECT?

The TMP6431DECT supports continuous operation up to +150 °C when used in the SOT-5X3 (DYA) package variant. In the X1SON (DEC) package-such as the TMP6431DECT-the maximum rated operating temperature is +125 °C. This distinction is defined in the device comparison table and confirmed in Section 7.3 of the datasheet. Exceeding these limits may accelerate long-term drift or compromise reliability. Always verify package type and corresponding thermal ratings before final design validation.

Does TMP6431DECT require external linearization circuitry?

No, TMP6431DECT does not require external linearization circuitry. Its silicon-based PTC structure delivers a highly linear resistance-vs.-temperature curve (±0.2% TCR tolerance), enabling direct use with simple voltage dividers or current-source biasing. Unlike NTC thermistors-which demand parallel resistors or complex polynomials-TMP6431DECT supports straightforward polynomial or lookup-table conversion. TI's Thermistor Design Tool generates application-specific R–T tables based on actual bias conditions, ensuring accuracy without added components.

What is the recommended bias current for TMP6431DECT?

The recommended bias current for TMP6431DECT is 42.553 µA, as specified in Section 7.5 of the datasheet for electrical characterization. This value balances linearity, self-heating error (<0.05 °C), and signal-to-noise ratio across the full temperature range. While operation up to 100 µA is permitted, higher currents increase self-heating and reduce measurement accuracy-especially above 85 °C. For ratiometric ADC interfaces, maintaining 42.553 µA ensures optimal TCR stability and matches TI's published R–T tables.

How does TMP6431DECT provide built-in fail-safe behavior?

TMP6431DECT provides built-in fail-safe behavior through its positive temperature coefficient: during a short-to-supply fault, rising current causes increased self-heating, which raises resistance and inherently limits further current flow-preventing thermal runaway. This contrasts with NTCs, whose resistance drops under overtemperature, creating destructive positive feedback. The fail-safe mechanism is intrinsic to the silicon PTC structure and requires no external circuitry, making TMP6431DECT suitable for safety-critical thermal cutoff applications in motor drives and power supplies.

Is TMP6431DECT pin-compatible with other TMP6x devices?

Yes, TMP6431DECT is pin-compatible with other TMP6x variants in the same X1SON (DEC) package-including TMP6131DECT and TMP6331DECT-as all share identical 2-pin pinout (pin 1 = –, pin 2 = +) and 0.60 mm × 1.00 mm body dimensions. However, R25 values differ (10 kΩ, 47 kΩ, 100 kΩ), so direct substitution requires verification of bias network compatibility and ADC scaling. No changes to PCB layout are needed when swapping within the DEC package family.