STDS75DS2E STMICROELECTRONICS [STMicroelectronics], STDS75DS2E Datasheet

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Digital temperature sensor and thermal watchdog Features ■ Measures temperatures from –55°C to +125°C (–67°F to +257°F) – ±2°C Accuracy from –25°C to +100°C (max) ■ Low operating current: 125µA (typ) ■ No external components required 2 ■ 2-wire I ...

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Contents 1 Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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Data valid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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Summary description The STDS75 is a high-precision CMOS (Digital) temperature sensor IC with a Delta-Sigma analog-to-digital (ADC) converter and page 7 targeted for general applications such as personal computers, system thermal management, electronics equipment, ...

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The measured temperature value is compared with a temperature limit (which is stored in the 16-bit (T ) READ/WRITE register), and the hysteresis temperature (which is stored in OS the 16-bit (T ) READ/WRITE register). If the measured value exceeds ...

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Figure 2. Connections (SO8 and TSSOP8) 1. SDA and OS/INT are open drain. Note: See Pin descriptions on page 9 Figure 3. Functional block diagram Temperature Sensor and Analog-to-Digital Converter (ADC 8/37 ...

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Pin descriptions See Figure 1 on page 7 to this device. 1.3.1 SDA (open drain) This is the Serial Data Input/Output pin for the 2-wire serial communication port. 1.3.2 SCL This is the Serial Clock Input pin for the ...

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Operation After each temperature measurement and analog-to-digital conversion, the STDS75 stores the temperature as a 16-bit two’s complement number in the 2-byte temperature register (see Table 8: Temperature register the temperature is positive or negative: ● for positive numbers ...

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Applications information STDS75 digital Temperature Sensors are optimal for thermal management and thermal protection applications. They require no external components for operations except for pull- up resistors on SCL, SDA, and OS/INT outputs. A 0.1µF bypass capacitor is recommended. ...

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Thermal alarm function The STDS75 thermal alarm function provides user-programmable thermostat capability and allows the STDS75 to function as a standalone thermostat without using the serial interface. The OS/INT output is the alarm output. This signal is an open ...

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Interrupt mode In Interrupt mode, the OS/INT output first becomes active when the measured temperature exceeds the T value a consecutive number of times equal to the FT value in the OS Configuration register. Once activated, the OS/INT can ...

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Fault tolerance For both Comparator and Interrupt modes, the alarm “fault tolerance” setting plays a role in determining when the OS/INT output will be activated. Fault tolerance refers to the number of consecutive times an error condition must be ...

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Temperature data format Table 3 shows the relationship between the output digital data and the external temperature for 12-bit resolution. Temperature data for Temperature, T 11-bit, and 12-bit depending upon the resolution bits RC1, RC0 (Bits 6 and 5) ...

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Functional description The STDS75 registers have unique pointer designations which are defined in page 16. Whenever any READ/WRITE operation to the STDS75 register is desired, the user must “point” to the device register to be accessed. All of these ...

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Configuration register The Configuration register is used to store the device settings such as Device Operation mode, OS/INT Operation mode, OS/INT Polarity, and OS/INT Fault Queue. The Configuration register allows the user to program various options such as conversion ...

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Temperature register The Temperature register is a two-byte (16-bit) “Read only” register (see page 18). Digital temperatures from the ADC are stored in the Temperature Register in two’s complement format, and the contents of this register are updated each ...

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Hysteresis temperature register (T T Register is a two-byte (16-bit) READ/WRITE register that stores the user- HYS programmable lower trip-point temperature for the thermal alarm in two’s complement format (see Table 9). This register defaults to 75°C at power-up ...

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Serial interface Writing to and reading from the STDS75 registers is accomplished via the two-wire serial interface protocol which requires that one device on the bus initiates and controls all READ and WRITE operations. This device is called the ...

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Data valid The state of the data line represents valid data when after a start condition, the data line is stable for the duration of the high period of the clock signal. The data on the line may be ...

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Acknowledge Each byte of eight bits is followed by one Acknowledge Bit. This Acknowledge Bit is a low level put on the bus by the receiver whereas the master generates an extra acknowledge related clock pulse (see generate an ...

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READ mode In this mode the master reads the STDS75 slave after setting the slave address (see Figure 8). Following the WRITE mode Control Bit (R/W=0) and the Acknowledge Bit, the word address 'An' is written to the on-chip ...

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Figure 9. Typical 2-byte READ from preset pointer location (e.g. temp - Start Address Byte by Master Figure 10. Typical pointer set followed by an immediate READ for 2-byte register (e.g. ...

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WRITE mode In this mode the master transmitter transmits to the STDS75 slave receiver. Bus protocol is shown in Figure 12. Following the START condition and slave address, a logic '0' (R placed on the bus ...

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Figure 14. T and Start Address Byte by Master Most Significant Data Byte 26/37 WRITE HYS ...

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Typical operating characteristics Figure 15. Temperature variation vs. voltage 140 120 100 –20 –40 – Voltage (V) –20 0.5 85 110 125 5 6 AI12258 27/37 ...

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Maximum rating Stressing the device above the rating listed in the “Absolute Maximum Ratings” table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above ...

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DC and AC parameters This section summarizes the operating measurement conditions, and the DC and AC characteristics of the device. The parameters in the DC and AC characteristics Tables that follow, are derived from tests performed under the Measurement ...

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Table 13. DC and AC characteristics Sym Description V Supply voltage DD V supply current, active DD temperature conversions supply current, DD communication only Standby supply current, I DD1 serial port inactive Accuracy for corresponding range 2.7V ...

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Figure 16. Bus timing requirements sequence SDA tBUF tHD:STA SCL P S Table 14. AC characteristics Sym f SCL clock frequency SCL t Time the bus must be free before a new transmission can start BUF t SDA and SCL ...

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Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner ...

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Figure 17. SO8 – 8-lead plastic small package outline A2 Note: Drawing is not to scale. Table 15. SO8 – 8-lead plastic small outline package mechanical data Symb Typ ccc D 4.90 E 6.00 E1 ...

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Figure 18. MSOP8 (TSSOP8) – 8-lead, thin shrink small package (3mm x 3mm) outline A ccc Note: Drawing is not to scale. Table 16. MSOP8 (TSSOP8) – 8-lead, thin shrink small package (3mm x 3mm) outline mechanical data Sym Typ ...

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Part numbering Table 17. Ordering information scheme Example: Device type STDS75 Package M = SO8 DS = MSOP8 (TSSOP8) Temperature range 2 = –55 to 125°C Shipping method F = ECOPACK package, Tape & Reel E=ECOPACK package, Tube 1. ...

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Revision history Table 18. Document revision history Date 28-Nov-2005 08-May-06 22-Jan-2007 01-Mar-2007 06-Jun-2007 36/37 Revision 1 Initial release. Update characteristics, diagrams (Figure 10, 11, 2 12, 13, 14, 15; Table 12, 13, ...

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Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any ...