Remote Temperature Sensors Include Local Sensor In SOT23 Package

Said to be the smallest remote junction temperature sensors with a built-in local temperature sensor, the TMP421 (one channel) and TMP422 (two channels) boast a remote sensor accuracy of ±1°C (maximum) and a local temperature sensor range of ±1.5°C. The sensors also feature a two-wire/SMBus serial interface as well as multiple addresses. The remote temperature sensor diode-connected transistors are typically low-cost NPN or PNP types or diodes that are an integral part of microprocessors, microcontrollers, and FPGAs. Other features include series resistance cancellation, programmable non-ideality factor, and diode fault detection. The sensors operate over a temperature range of -40°C to +125°C, with a remote temperature range of up to 150°C. For maximum power savings, the device circuitry (other than the serial interface) can be shut down, reducing current consumption to typically less than 3 µA. The RoHS-compliant TMP421 and TMP422 are available now in an 8-lead SOT23 package. The TMP421 costs $1.25 each, and the TMP422 is $1.65 each, both in 1,000-piece quantities. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924.