The TMP421 and TMP422, from Texas Instruments Incorporated (TI) (NYSE: TXN), is the industry’s smallest remote junction temperature sensors with a built-in local temperature sensor. The single remote channel TMP421 and dual remote channel TMP422 provide remote sensor accuracy of +/-1C (maximum) and a local temperature sensor range of +/-1.5C (maximum). Both sensors are RoHS compliant and can be used in numerous applications including LCD/DLP®/LCOS projectors, servers, central office telecom equipment, and laptop computers. They are also suitable for industrial controllers, processor/FPGA temperature monitoring and storage area networks.
The TMP421 and TMP422 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-type transistors or diodes that are an integral part of microprocessors, microcontrollers and FPGAs. The TMP421 and TMP422 also include series resistance cancellation, programmable non-ideality factor and diode fault detection.
The sensors operate on a standard I2C/SMBus compatible, two-wire interface over a temperature range of -40°C to 125°C, with a remote temperature range of up to 150C. For maximum power savings, the device circuitry (other than the serial interface) can be shut down, thereby reducing current consumption to typically less than 3uA.
The TMP421 and TMP422 are available now from TI and its authorized distributors in an 8-lead SOT23 package. The TMP421 is priced at $1.25 each in 1,000-piece quantities and the TMP422 is priced at $1.65 each in 1,000-piece quantities (suggested resale pricing).
TMP421 and TMP422