DS1731

Features:

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


Application

Network Routers and Switches
Cellular Base Stations
Portable Products 
Any Space-Constrained Thermally Sensitive Product


Pinout




Specifications

Voltage on any Pin Relative to Ground ...........................-0.5V to +6.0V
Operating Temperature Range................................ -55°C to +125°C
Storage Temperature Range................................... -55°C to +125°C
Solder Dip Temperature (10s) See IPC/JEDEC J-STD-020A Specification
Reflow Oven Temperature....................................................... +220°C


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.

Pin descriptions for the DS1631/DS1631A/DS1731 are provided in Table 2 and user-accessible registers are summarized in Table 3. A functional diagram is shown in Figure 1.