Texas Instruments LMT85LPM

Overview

LMT85LPM from Texas Instruments is a precision analog-output CMOS temperature sensor in TO-92 through-hole package with formed leads, delivering ±0.4°C typical accuracy over –50°C to 150°C, −8.2 mV/°C average output slope, and 5.4 µA quiescent current at 1.8 V supply-enabling low-power thermal monitoring in smoke detectors and automotive powertrain modules.

For engineers reviewing the LMT85LPM datasheet, LMT85LPM pinout, LMT85LPM application, or LMT85LPM equivalent, this page provides verified package mapping (TO-92, 3-pin, formed leads), confirmed thermal time constant (10 s typical at 1.2 m/s airflow), validated push-pull output drive (±50 µA), and real-world substitution guidance for thermistor-replacement designs requiring linear analog voltage output.

Technical Context

The LMT85LPM uses a forward-biased base-emitter junction as its sensing element, buffered by a rail-to-rail CMOS amplifier with push-pull output stage-ensuring low-impedance sourcing and sinking capability. Its transfer function follows a slight parabolic shape, accurately modeled by the published Transfer Table (−50°C to 150°C) and approximated linearly as V_OUT = 1569 mV − 8.2 mV/°C × T.

Thermal response is optimized via direct die-to-GND thermal path: the backside of the die connects electrically and thermally to the GND pin, enabling rapid heat conduction from external mounting surfaces. Self-heating error remains below 0.014°C under typical load conditions (5.4 µA supply current, 2 µA output load).

Key Specifications

Pinout & Package

Package: TO-92 (3-pin, formed leads), body size 4.30 mm × 3.50 mm, through-hole mounting with lead-forming for vertical or horizontal PCB installation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog-output temperature sensor applications.

Compared with LMT85LPG, the LMT85LPM trades marginally slower thermal response for mechanical flexibility in vertical mounting; compared with LMT84DCK, it retains higher signal-to-noise ratio per degree and eliminates need for enable logic-making it optimal for cost-sensitive, through-hole thermal monitoring where simplicity and linearity are prioritized.

Availability

LMT85LPM is available at Aetrix Electronics and suitable for smoke and heat detectors, automotive powertrain modules, and drone battery management systems requiring stable component supply across extended production lifecycles.

Supply support for LMT85LPM 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 headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing solutions for industrial, automotive, and consumer markets.

The LMT85 family was developed specifically to replace NTC thermistors in applications demanding linear analog output, low power, and wide temperature range-delivering factory-calibrated accuracy without external compensation circuitry.

FAQ

What is the pin configuration of the LMT85LPM?

The LMT85LPM uses a 3-pin TO-92 package with formed leads. Pin 1 is VDD, Pin 2 is OUT, and Pin 3 is GND (viewed from flat side with leads down). This matches the LP variant pinout and differs from LMT85LPG (Pin 1 = OUT, Pin 2 = GND, Pin 3 = VDD). Always verify orientation using TI's official mechanical drawing SLMS227.

Does the LMT85LPM require an external capacitor on the output?

No, the LMT85LPM is stable driving capacitive loads up to 1100 pF without external series resistance. For typical microcontroller ADC inputs (≤100 pF), no output capacitor is needed. Only add a series resistor (e.g., 800 Ω) if driving >1 nF loads-per TI's Figure 12 and Table 4 in SNIS168E.

Can the LMT85LPM operate from a 1.8-V supply while maintaining full accuracy?

Yes-the LMT85LPM is fully specified from 1.8 V to 5.5 V. At 1.8 V, its ±0.4°C typical accuracy (−50°C to +150°C) and −8.2 mV/°C gain remain valid per Section 7.5 of the datasheet. Supply noise rejection is maintained via internal regulation, and power-on time stays ≤1.9 ms.

How does the LMT85LPM compare to thermistors in terms of calibration effort?

The LMT85LPM eliminates thermistor-specific calibration: it delivers factory-trimmed linearity (±0.4°C typical) and a published Transfer Table covering −50°C to +150°C. Unlike NTCs requiring complex β-parameter or Steinhart-Hart equations, the LMT85LPM supports simple two-point linear interpolation or direct lookup-reducing firmware development time and runtime CPU load.

Is the LMT85LPM suitable for automotive applications?

The LMT85LPM itself is not AEC-Q100 qualified; however, the LMT85-Q1 variant (e.g., LMT85DCK-Q1) is automotive-grade. For non-safety-critical automotive infotainment or cabin climate modules, LMT85LPM may be used-but design validation per ISO 16750 and customer-specific requirements is mandatory before deployment.