LMT84LPM Analog Temperature Sensor: Complete Technical Guide, Specs & Alternatives | XAIPART

What Is the LMT84LPM and Why Should Engineers Choose It?

The Texas Instruments LMT84LPM is a precision CMOS analog output temperature sensor in a TO-92-3 through-hole package that operates from a single supply as low as 1.5V while drawing just 5.4 uA of quiescent current. Its linear output voltage changes at -5.5 mV per degree C across a -50C to +150C measuring range, with +/-0.4C typical accuracy (+/-2.7C maximum) per the TI LMT84 datasheet. The Class-AB push-pull output sources and sinks load current directly, so most designs connect it straight to a microcontroller ADC without a buffer amplifier. Power-on time is only 0.7 ms, enabling aggressive duty cycling in battery products. As of 2026-09-02, the LMT84LPM is in stock at XAIPART with 99,999 units available, MOQ 1, priced from $0.62 at single units down to $0.27 at 1,000 units. The part is active (non-obsolete), RoHS compliant, and an automotive LMT84-Q1 variant qualified to AEC-Q100 Grade 0 is available for automotive programs.

Unlike a thermistor, the LMT84 delivers a linear, calibrated transfer function with no divider resistors or lookup tables. Unlike digital sensors such as the TMP117, it needs no I2C bus, no configuration registers, and no firmware protocol stack. That simplicity, combined with micropower consumption, makes it one of the most cost-effective temperature sensing choices on the market today.

How Do You Design In the LMT84LPM? A Practical Technical Guide

Understanding the Transfer Function

The LMT84 output is inversely proportional to temperature at a gain of -5.5 mV/C. This means output voltage decreases as temperature rises, so you must invert the transfer function in firmware: temperature = (measured voltage offset - measured voltage) / 5.5 mV/C. The transfer function is linear and monotonic across the full -50C to +150C range, which keeps ADC math simple and avoids piecewise calibration.

Power Supply and Bypassing

The sensor operates from a single supply with a minimum of 1.5V, allowing direct connection to lithium coin cells without a boost converter. Place a 0.1 uF bypass capacitor close to the VDD supply pin for stable ADC readings. The 5.4 uA quiescent current keeps the bypass network and the sensor negligible on any power budget.

Driving the ADC

The Class-AB push-pull output stage has strong source and sink capability, so it drives ADC inputs and moderate loads directly. In HVAC applications this same output strength tolerates long wiring runs between the sensor and the controller board. In IoT nodes, a 10-bit ADC referenced at 1.8V resolves about 0.6C steps with the -5.5 mV/C gain, adequate for comfort-level environmental reporting.

Duty Cycling for Battery Life

With a 0.7 ms power-on time, you can shut the sensor down between readings and sample temperature in sub-millisecond windows. Combined with 5.4 uA quiescent current, this pushes average consumption far below 1 uA in wireless loggers, supporting multi-year battery life from a small lithium cell.

LMT84LPM Pinout (TO-92-3)

Per the TI datasheet flat-facing view: pin 1 is GND, pin 2 is VTEMP (the analog output at -5.5 mV/C), and pin 3 is VDD. Always confirm against the latest datasheet revision, because TO-92 pin conventions vary between manufacturers and family members.

Which Alternatives Compare to the LMT84LPM?

All alternatives below are drawn from verified XAIPART database data:

Summary: the LMT84-Q1 is the closest drop-in replacement (same silicon function and pinout, AEC-Q100 Grade 0 qualified). Within the family, the LMT85 offers pin-selectable gain when ADC resolution is limited, and the LM94022 offers gain options on a higher supply rail. Cross-brand, the Analog Devices TMP36 provides similar analog functionality but a different gain and pinout, requiring firmware scaling and supply rail changes.

What Is the Market Position and Supply Situation for the LMT84LPM?

The LMT84 is an active, non-obsolete TI product, so lead times are typically short (days to a few weeks) rather than the long lead times common for allocated sensors. As of 2026-09-02, XAIPART lists 99,999 units in stock with MOQ 1 and tiered pricing of $0.62 (qty 1+), $0.52 (10+), $0.39 (100+), $0.32 (500+), and $0.27 (1000+). Per DigiKey, stocked quantities ship the same day. The part is RoHS compliant. [DATA_NEEDED: lifecycle stage classification beyond active status, e.g., NRND forecasts]

What Should Buyers Watch Next for the LMT84 Family?

Three trends anchor directly to verified specs. First, low-voltage battery architectures: the 1.5V minimum supply and 5.4 uA quiescent current position the LMT84 for direct coin-cell designs without boost converters, a growing segment in IoT and wearables. Second, automotive qualification demand: the LMT84-Q1's AEC-Q100 Grade 0 rating for -40C to +150C makes the family relevant as always-on body electronics expand; using the Q1 part removes qualification risk in ISO 26262-relevant monitoring paths. Third, analog versus digital economics: the LMT84 trades the +/-0.1C digital accuracy of the TMP117 for cost, simplicity (no I2C stack), and micropower duty-cycled sampling with 0.7 ms wake time. Buyers who need calibration-grade precision should specify the TMP117-Q1; those optimizing cost and power should standardize on the LMT84. Monitor pricing tiers as of 2026-09-02 before volume commitments; the $0.27 unit price at 1,000 pieces undercuts most digital alternatives.