Texas Instruments LM70CIMM-3-TI

Overview

LM70CIMM-3-TI from Texas Instruments is a SPI/MICROWIRE-compatible 10-bit plus sign digital temperature sensor in VSSOP-8 package, delivering 0.25°C resolution over −55°C to +150°C, with shutdown current <12 μA and supply range 2.65V–5.5V. It serves as a die-temperature sensing element in thermal management circuits for hard disk drives and office electronics.

For engineers reviewing the LM70CIMM-3-TI datasheet, LM70CIMM-3-TI pinout, LM70CIMM-3-TI application, or LM70CIMM-3-TI equivalent, key selection factors include its ΔΣ ADC architecture, tri-state serial I/O timing, shutdown command protocol (0xFF write), and VSSOP-8 thermal resistance (θ_JA = 200°C/W).

Technical Context

The LM70CIMM-3-TI integrates a band-gap temperature sensor with a 10-bit plus sign delta-sigma ADC, outputting data in two's complement format where one LSB equals 0.25°C. Its serial interface operates in slave mode, compatible with both SPI and MICROWIRE protocols using SI/O bidirectional data line and Schmitt-triggered SC clock.

Communication requires 32 serial clocks per full transaction: 16 clocks for temperature readback (MSB-first, 11-bit signed value), followed by 16 clocks for configuration write - including shutdown activation via 0xFF command. The device powers up in continuous conversion mode and supports manufacturer ID readback during shutdown.

Key Specifications

Pinout & Package

VSSOP-8 package (Package Drawing DGK), 3.0 mm × 3.0 mm body, 0.65 mm pitch, exposed pad not present. Thermal resistance θ_JA = 200°C/W when mounted on standard PCB with 2 oz copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6602ESA+ and ADT7301ARMZ, the LM70CIMM-3-TI offers optimal balance of SPI compatibility, wide supply range, ultra-low shutdown current, and VSSOP-8 footprint - making it ideal for cost-sensitive, space-constrained thermal monitoring where 0.25°C resolution suffices.

Availability

LM70CIMM-3-TI is available at Aetrix Electronics and suitable for hard disk drives, office electronics, industrial PCs, electronic test equipment, and system thermal management requiring stable component supply across extended temperature ranges.

Supply support for LM70CIMM-3-TI 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 chips for industrial, automotive, and consumer applications.

The LM70 series was developed specifically for low-cost, SPI-based thermal monitoring in space-constrained storage and computing platforms - emphasizing simplicity, low power, and robust serial interface operation.

FAQ

What is the operating temperature range of the LM70CIMM-3-TI?

The LM70CIMM-3-TI operates from −55°C to +150°C. This full-range specification is validated per the datasheet's Operating Ratings table and applies across the entire supply voltage range of 2.65V to 5.5V. At extremes, accuracy degrades to +3.5/−2.0°C, while tighter ±2.0°C tolerance holds from −40°C to +85°C - making LM70CIMM-3-TI suitable for both industrial and commercial thermal sensing roles.

How does the LM70CIMM-3-TI enter and exit shutdown mode?

The LM70CIMM-3-TI enters shutdown mode by receiving an 0xFF command during the write phase of a 32-clock SPI transaction - specifically, writing XX FF to the configuration register. It exits shutdown upon any subsequent valid command (e.g., 0x00) or power cycle. In shutdown, LM70CIMM-3-TI draws ≤12 μA and outputs its Manufacturer ID (0x81xx) on SI/O, enabling firmware identification without waking the sensor.

What is the meaning of "10-bit plus sign" resolution in the LM70CIMM-3-TI?

"10-bit plus sign" means the LM70CIMM-3-TI outputs an 11-bit two's complement word: one sign bit plus ten magnitude bits. Each LSB represents 0.25°C, yielding a total span of −55°C to +150°C with uniform 0.25°C quantization steps. This format allows direct interpretation of temperature data without scaling math - for example, 0x001F = 0°C, 0x003F = +0.25°C, and 0xFFF = −0.25°C.

Does the LM70CIMM-3-TI require external components for basic operation?

Yes - the LM70CIMM-3-TI requires a 0.1 μF ceramic bypass capacitor between V+ and GND, placed as close as possible to the pins. No external oscillator, reference, or filtering components are needed due to its integrated ΔΣ ADC and band-gap sensor. Pull-up resistors are unnecessary because SI/O uses tri-state control synchronized to CS and SC, eliminating bus contention risks.

Is the LM70CIMM-3-TI RoHS compliant and what is its moisture sensitivity level?

Yes, the LM70CIMM-3-TI/NOPB variant is RoHS compliant (Green, lead-free, no Sb/Br) and rated MSL Level-1 (unlimited floor life at ≤30°C/60% RH). Per TI's Package Option Addendum, it uses Sn (matte tin) lead finish and is qualified for reflow up to 260°C peak temperature - confirming full compatibility with standard lead-free PCB assembly processes.