Composed of thermocouples, RTDs, thermistors, and external diodes

Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of a new high-performance digital temperature measurement IC product (product name: LTC2986).

The new product is characterized by the ability to directly quantify any combination of thermocouples, RTDs, thermistors, and external diodes with a 0.1°C alignment and a 0.001°C resolution.

The LTC2986 is based on the award-winning LTC2983 and LTC2984, with three new operating modes added and the number of analog inputs reduced from 20 to 10. Thanks to these new operating modes, support for external overvoltage protection resistors shared among various types of sensors—such as temperature sensors with analog outputs when powered on, and temperature-independent sensors like pressure or other voltage output sensors—has also been further improved.

The LTC2986's high-performance analog front-end (AFE) integrates a buffered ADC with low noise and offset, as well as all the excitation and control circuits required for each sensor. Measurements are performed under the control of a digital engine, which combines all the algorithms and linearization required for each measurement.

This device perfectly measures microvolt-level signals via thermocouples and rationmetric resistance via RTDs and thermistors, performs linearization, and displays the results in Celsius (°C) or Fahrenheit (°F). Up to 10 analog channels can be utilized, supporting up to 9 thermocouples, 4 RTDs, 4 thermistors, and/or 10 diodes. The SPI interface works with almost any digital system, and the LTC2986 can be optimized more easily through an extensive drop-down menu-based software support system.

The LTC2986, which offers simple yet rich functionality, interfaces with a wide range of temperature sensors, including B, E, J, K, N, S, R, and T type thermocouples, 2-, 3-, or 4-wire RTDs, 2.25kΩ to 30kΩ thermistors, and temperature sensing diodes. The LTC2986 can operate with ground-referenced sensors without the need for amplifiers, negative supplies, or level conversion circuits.

Signals are quantified simultaneously using three high-accuracy 24-bit Δ∑ ADCs with an internal 15 ppm/°C reference. Automatic thermocouple cold junction compensation is possible regardless of the external sensor used. Linearization algorithms for all mainstream sensors are integrated into the chip. Custom sensors can be linearized via custom coefficients programmed and stored on the chip.

The onboard EEPROM (LTC2986-1) is used to store user-configured data and customized sensor counts, eliminating the need to use any ICs or sensors programmed by the host processor. The dual programmable excitation current source features reverse current and current range that improve accuracy and reduce noise. To ensure accurate resistance measurement, the reverse current eliminates the thermocouple effect in the resistance sensor. Sensor-specific error detection functions notify the user of short circuits, open circuits, over-temperature, under-temperature, and ADC over-range.

The LTC2986 is supplied for commercial, industrial, and automotive applications, with operating temperature ranges of 0°C to 70°C, –40°C to 85°C, and –40°C to 125°C, respectively. Currently, the LTC2986 is available in a RoHS-compliant 7mm x 7mm LQFP-48 package and is pin-compatible with the LTC2983 and LTC2984. Pricing starts at $16.56 per unit for quantities of 1,000.