DESCRIPTION
The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature readings over a -55°C to +125°C range. The DS1631 and DS1631A thermometer accuracy is ±0.5°C from 0°C to +70°C with 3.0V ≤ VDD ≤ 5.5V, and the DS1731 accuracy is ±1°C from -10°C to +85°C with 3.0V ≤ VDD ≤ 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip points (TH and TL). The TH and TL registers and thermometer configuration settings are stored in NV EEPROM so they can be programmed prior to installation. In addition, the DS1631A automatically begins taking temperature measurements at power-up, which allows it to function as a stand-alone thermostat. Communication with the DS1631/DS1631A/DS1731 is achieved through a 2-wire serial interface, and three address pins allow up to eight devices to be multidropped on the same 2-wire bus.

FEATURES
ƒ DS1631 and DS1631A Provide ±0.5°C Accuracy over a 0°C to +70°C Range
ƒ DS1731 Provides ±1°C Accuracy over a -10°C to +85°C Range
ƒ DS1631A Automatically Begins Taking Temperature Measurements at Power-Up
ƒ Operating Temperature Range: -55°C to +125°C (-67°F to +257°F)
ƒ Temperature Measurements Require No External Components
ƒ Output Resolution is User-Selectable to 9, 10, 11, or 12 Bits
ƒ Wide Power-Supply Range (+2.7V to +5.5V)
ƒ Converts Temperature-to-Digital Word in 750ms (max)
ƒ Multidrop Capability Simplifies Distributed Temperature-Sensing Applications
ƒ Thermostatic Settings are User-Definable and Nonvolatile (NV)
ƒ Data is Read/Written Through 2-Wire Serial Interface (SDA and SCL Pins)
ƒ All Three Devices are Available in 8-Pin μSOP Packages and the DS1631 is Also Available in a 150mil SO package—see Table 1 for Ordering Information