The DS1621 Digital Thermometer and Thermostat provides 9-bit temperature readings, which indicate the temperature of the device. The thermal alarm output, TOUT, is active when the temperature of the device exceeds a user-defined temperature TH. The output remains active until the temperature drops below user defined temperature TL, allowing for any hysteresis necessary.
User-defined temperature settings are stored in nonvolatile memory so parts may be programmed prior to insertion in a system. Temperature settings and temperature readings are all communicated to/from the DS1621 over a simple 2-wire serial interface.
The DS1621 measures temperature using a bandgap-based temperature sensor. A delta-sigma analog-to digital converter (ADC) converts the measured temperature to a digital value that is calibrated in °C; for°F applications, a lookup table or conversion routine must be used.