Analog Devices Inc./Maxim Integrated

The DS1626 and DS1726 digital thermometers/thermostats provide temperature measurements and stand-alone thermostat capability over a -55°C to +125°C range. The DS1626 offers ±0.5°C accuracy from 0°C to +70°C and the DS1726 has ±1°C accuracy from -10°C to +85°C. The resolution of the measured temperature is user selectable from 9 to 12 bits. Communication with the DS1626 and DS1726 is achieved through a 3-wire serial bus.The DS1626 and DS1726 offer thermostatic functionality with three dedicated thermostat outputs (THIGH, TLOW, and TCOM), and overtemperature (TH) and undertemperature (TL) user-programmable thresholds stored in on-chip EEPROM. For stand-alone thermostat operation, THand TLcan be programmed prior to installation, and the DS1626/DS1726 can be configured to automatically begin taking temperature measurements at power-up. Table 1, in the full data sheet, summarizes the user-accessible registers. Figure 1, in the full data sheet, shows a functional diagram.ApplicationsAny Space-Constrained Thermally Sensitive ApplicationConsumer ProductsIndustrial ControlsThermostatic Controls

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 (THand TL). The THand TLregisters 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.ApplicationsMedicalNetworkingPersonal ComputingRouters/SwitchesTest Measurement SystemsWireless Base Stations

The DS1744 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 32k x 8 NV SRAM. User access to all registers within the DS1744 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the date of each month and leap year are made automatically. The RTC clock registers are double-buffered to avoid access of incorrect data that can occur during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1744 also contains its own power-fail circuitry that deselects the device when the VCCsupply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCCas errant access and update cycles are avoided.

The DS1747 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 512k x 8 nonvolatile static RAM. User access to all registers within the DS1747 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour binary-coded decimal (BCD) format. Corrections for the date of each month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data that can occur during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1747 also contains its own power-fail circuitry that deselects the device when the VCCsupply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCCas errant access and update cycles are avoided.