Texas Instruments LM35DMX

Overview

LM35DMX from Texas Instruments is a precision centigrade temperature sensor IC with analog voltage output directly proportional to temperature, 10 mV/°C scale factor, ±0.4°C accuracy at 25°C, and full-range operation from −55°C to +150°C. It operates from 4 V to 30 V supply, draws less than 60 µA quiescent current, and delivers low-impedance output (0.1 Ω) for direct interfacing with ADCs or instrumentation amplifiers in industrial monitoring systems.

For engineers reviewing the LM35DMX datasheet, LM35DMX pinout, LM35DMX application, or LM35DMX equivalent, key selection criteria include its calibrated Celsius output, wafer-trimmed accuracy across extreme temperatures, minimal self-heating (<0.08°C in still air), and compatibility with single-supply systems requiring no external calibration or offset subtraction.

Technical Context

The LM35DMX implements a delta-V_BE temperature-sensing element buffered by a Class-A amplifier, delivering a linear analog output without internal compensation circuitry. Its transfer function is strictly V_OUT = 10 mV/°C × T, with no Kelvin-to-Celsius offset correction required.

It functions exclusively in analog sensing mode-no digital interface, configuration registers, or power-down states. Output sourcing capability is limited to 1 mA, while sinking is restricted to 1 µA; it cannot drive heavy capacitive loads (>50 pF) without series resistance or RC damping.

Key Specifications

Pinout & Package

The LM35DMX is housed in an 8-pin SOIC (D package) with 4.90 mm × 3.91 mm body size. Pin 1 is +VS, Pin 2 is VOUT, Pin 4 is GND; Pins 3, 5–8 are no-connect (N.C.). The case is not internally connected to any terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM35DZ/NOPB, LM35DMX offers identical performance in a production-optimized SOIC-8 tape-and-reel format; versus ADT7320TRZ-REEL7, LM35DMX provides simpler analog integration, lower system-level BOM count, and guaranteed operation down to −55°C without firmware dependencies.

Availability

LM35DMX is available at Aetrix Electronics and suitable for industrial process monitoring, power supply thermal management, and battery pack safety monitoring requiring stable component supply across long-lifecycle programs.

Supply support for LM35DMX 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 signal chain and power management solutions.

The LM35 series belongs to TI's precision analog temperature sensor product line, designed specifically for direct Celsius measurement in industrial, automotive, and consumer systems where calibration-free accuracy and wide operating range are critical.

FAQ

What is the operating temperature range of the LM35DMX?

The LM35DMX is rated for continuous operation from −55°C to +150°C. This full-range specification is validated per TI's production testing and applies across the entire supply voltage range (4 V to 30 V). At extremes, accuracy degrades to ±0.8°C at both T_MIN and T_MAX, while maintaining linearity within ±0.3°C typical non-linearity. The device's delta-V_BE core and SOIC packaging enable this extended range without external compensation.

Does the LM35DMX require external calibration or trimming?

No, the LM35DMX does not require external calibration or trimming. It is factory-calibrated at wafer level to deliver ±0.4°C accuracy at 25°C and ±0.8°C over its full −55°C to +150°C range. The 10 mV/°C transfer function is inherently stable with temperature and supply voltage - no offset adjustment, gain potentiometer, or software correction is needed for standard use cases.

Can the LM35DMX drive an ADC input directly?

Yes, the LM35DMX can drive most 12-bit and lower-resolution SAR or delta-sigma ADC inputs directly. Its 0.1 Ω output impedance and 1 mA sourcing capability ensure minimal loading error - for example, connecting to a 10 kΩ ADC input impedance introduces only 0.001% gain error. For higher-resolution ADCs (>14 bit) or noisy environments, a unity-gain buffer is recommended to preserve SNR.

What is the maximum capacitive load the LM35DMX can drive?

The LM35DMX can reliably drive up to 50 pF of capacitive load without oscillation or settling delay. Beyond that, instability may occur due to phase margin degradation. For loads >50 pF (e.g., long cables or ADC input capacitance), TI recommends adding a 75 Ω series resistor between VOUT and the load, optionally with a 0.2 µF to 1 µF capacitor from output to ground to form an RC damper network.

Is the LM35DMX pin-compatible with other LM35 variants like LM35D or LM35C?

No, the LM35DMX (SOIC-8) is not pin-compatible with LM35D (TO-92 or TO-220) or LM35C (TO-92). While all share the same functional pin assignments (+VS, VOUT, GND), the LM35DMX has five no-connect (N.C.) pins (3, 5–8) in its SOIC-8 package, whereas TO-92 and TO-220 versions are 3-pin devices. PCB layout and footprint must be redesigned for migration between packages.