Temperature Monitors

Temperature is the most frequently measured parameter in the world and is difficult to measure accurately. Thermocouples, as well as temperature-dependent resistance elements (RTDs and thermistors) and semiconductor elements (diodes), are commonly used to electrically measure temperature. While methods for extracting temperature from these elements are well known, accurately measuring temperatures to better than 0.5°C or 0.1°C accuracy is challenging. Digitizing these basic sensor elements requires expertise in analog circuit design, digital circuit design, and firmware development. Linear Technology offers temperature monitoring ICs that solve each of the unique challenges associated with standard or custom thermocouples, RTDs, thermistors, and diodes. Some of these new devices, like the 20-channel LTC2983 temp sensor, combine all analog circuitry necessary for each sensor type with temperature measurement algorithms and linearization data to directly measure each sensor and output the result in degrees C or degrees F. The 20-channel LTC2984 with EEPROM enables on-chip storage of channel configuration data and custom sensor coefficients, and facilitates the use of self-contained temperature sensing boards or modules.  The 10-channel LTC2986 provides additional support for external overvoltage protection, powered temperature sensors, and non-temperature related sensors such as pressure or other voltage output sensors.

Linear Technology’s diode-based temp monitors are equipped with series resistance cancellation and target a variety of board level measurement applications. If only measuring temperature, the LTC2997 single temperature monitor is a simple 2mm x 3mm device that measures an external temperature with ±0.25°C accuracy or its own internal temperature with ±0.5°C accuracy and provides a voltage-proportional-to-absolute-temperature (VPTAT) output. The LTC2995 takes the LTC2997 and adds temperature alerts and two voltage monitoring channels for a much more integrated solution. If a digital interface is required, the LTC2990/LTC2991 quad/octal I2C temperature monitors can be configured in up to 35 different ways, perfect for systems that need simple digital monitoring of combinations of temperature, voltage and current.

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