DS1629 2-Wire Digital Thermometer and Real-Time Clock FEATURES PIN CONFIGURATION Measures Temperatures from -55C to +125C Fahrenheit Equivalent is -67F to SDA 1 8 V DD SCL 2 7 OSC 257F ALRM 3 6 X1 Real-Time Clock Counts Seconds, Minutes, 5 GND 4 X2 Hours, Date of the Month, Month, Day of the SO Week, and Year with Leap Year (150 mils) Compensation Through the Year 2100 Thermometer Accuracy is 2.0C (typ) Thermometer Resolution is 9 Bits PIN DESCRIPTION (Expandable) SDA - 2-Wire Serial Data Input/Output Thermostatic and Time Alarm Settings Are SCL - 2-Wire Serial Clock User Definable Dedicated Open-Drain Alarm GND - Ground Output ALRM - Thermostat and Clock Alarm 32 Bytes SRAM for General Data Storage Output Data is Read From/Written to via a 2-Wire X1 - 32.768kHz Crystal Input Serial Interface (Open Drain I/O Lines) X2 - 32.768kHz Crystal Feedback Wide Power Supply Range (2.2V to 5.5V) Output Applications Include PCs/PDAs, Cellular OSC - Buffered Oscillator Output Telephones, Office Equipment, Data Loggers, V - Power-Supply Voltage (+2.2V to DD or Any Thermally Sensitive System +5V) 8-Pin (150-mil) SO Package DESCRIPTION The DS1629 2-wire digital thermometer and realt-ime clock (RTC) integrates the critical functions of a real-time clock and a temperature monitor in a small outline -8pin SO package. Communication to the DS1629 is accomplished via a w2i-re interface. The wide pow-ersupply range and minimal power requirement of the DS1629 allow for accurate time/temperature measurements in -pbowattereryed applications. The digital thermometer provides 9-bit temperature readings which indicate the temperature of the device. No additional components are required the device is truly a temperature-to-digital converter. The clock/calendar provides seconds, minutes, hours, day, date of the month, day of the week, month, and year. The end of the month date is automatically adjusted for months with less than 31 days, including corrections for leap years. It operates in either a 12- or 24-hour format with AM/PM indicator in 12-hour mode. The crystal oscillator frequency is internally divided, as specified by device configuration. An open-drain output is provided that can be used as the oscillator input for a microcontroller. 1 of 23 19-6849 Rev 11/13 DS1629 The open-drain alarm output of the DS1629 will become active when either the measured temperature exceeds the programmed ovetermperature limit (T) or current time reaches the programmed alarm H setting. The user can configure which event (time only, temperature only, either,o r neither) will generate an alarm condition. For storage of general system data or time/temperature daltoggia ng, the DS1629 features 32 bytes of SRAM. Applications for the DS1629 include personal computePrsD/ As, cellular telephones, office equipment, thermal da taloggers, or any microprocessor-based, thermally-sensitive system. ORDERING INFORMATION PART TOP MARK PIN-PACKAGE DS1629S+ DS1629 8 SO (150 mils) DS1629S+T&R DS1629 8 SO (150 mils) (2500 piece) +Denotes a lead(Pb)-free/RoHS-compliant package. T&R = Tape and reel. DETAILED PIN DESCRIPTION Table 1 PIN NAME FUNCTION 1 SDA Data Input/Output Pin for 2-Wire Serial Communication Port 2 SCL Clock Input/Output Pin for 2-Wire Serial Communication Port Alarm Output. Open drain time/temperature alarm output with configurable active 3 ALRM state. 4 GND Ground 5 X2 32.768kHz Feedback Output 6 X1 32.768kHz Crystal Input 7 OSC Oscillator Output. Open-drain output used for microcontroller clock input. 8 V Supply Voltage. 2.2V to 5.5V input power pin. DD OVERVIEW A block diagram of the DS1629 is shown in Figure 1. The DS1629 consists of six major components: 1. Direct-to-digital temperature sensor 2. Real-time clock 3. 2-wire interface 4. Data registers 5. Thermal and clock alarm comparators 6. Oscillator divider and buffer The factory-calibrated temperature sensor requires no external components. The very first time the DS1629 is powered up it begins temperature conversions, and performs conversions continuously. The host can periodically read the value in the temperature register, which contains the last completed conversion. As conversions are performed in the background, reading the temrpeature register does not affect the conversion in progress. The host can modify DS1629 configuration such that it does not power up in theco nvaeutrto -or continuous convert modes. This could be beneficial in power-sensitive applications. 2 of 23