STDS75 STMicroelectronics, STDS75 Datasheet

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... Shutdown mode to minimize power consumption ■ Separate open drain output pin operates as an interrupt or comparator/thermostat output (dual purpose event pin) ■ Packages: – SO8 (a) – MSOP8 (TSSOP8) a. Contact local ST sales office for availability June 2007 SO8 (M) MSOP8 (TSSOP8) (DS) Rev 5 STDS75 1/37 www.st.com 1 ...

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

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

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... Programmable resolution configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 8. Temperature register format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 9. T and T register format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 OS HYS Table 10. STDS75 serial bus slave addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Table 11. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Table 12. Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Table 13. DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Table 14. AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Table 15. SO8 – 8-lead plastic small outline package mechanical data Table 16. MSOP8 (TSSOP8) – ...

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

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... Three pins (A0, A1, and A2) are available for address selection, and enable the user to connect devices on the same bus without address conflict. In addition, the serial interface gives the user easy access to all STDS75 registers to customize operation of the device. 1.2 ...

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... SDA and OS/INT are open drain. Note: See Pin descriptions on page 9 Figure 3 on page 8 (1) SDA SCL STDS75 (1) O.S./INT GND for details. Type/Direction (1) Input/ Output Serial data input/output Input Serial clock input (1) Output Over-limit signal/interrupt alert output Supply ground ...

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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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... Since temperature conversions are performed in the background, reading the temperature register does not affect the operation in progress. Bits 3 through 0 of the temperature register are hardwired to logic '0.' When the STDS75 is configured for 12-bit resolution, the 12MSBs (Bits 15 through 4) of the temperature register will contain temperature data ...

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... 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. The sensing device of STDS75 is the chip itself. The typical interface connection for this type of digital sensor is shown in Intended Applications include: ● ...

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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 drain output, and at power-up, this pin is configured with active-low polarity by default. ...

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... STDS75 configured to have a fault tolerance of 2. The interrupt/clear process is cyclical between T Figure 5. OS output temperature response diagram OS Output - Comparator mode OS Output - Interrupt mode 1. This assumes that a READ has occurred. Note: The STDS75 is configured to have a fault tolerance this example. Figure 5 illustrates typical OS output temperature and HYS T OS ...

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... STDS75 will go into a low-power standby state. The OS/INT output will be cleared if the thermostat is operating in Interrupt mode and the OS/INT will remain unchanged in Comparator mode. The 2-wire interface remains operational in shutdown mode, and writing a '0' to the SD Bit returns the STDS75 to normal operation. 14/37 STDS75 (Consecutive Faults) ...

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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 user-accessible registers can be accessed via the digital serial interface at ...

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... Table 6). The entire register is volatile and thus powers-up in its default state only. Table 6. Configuration register format MSB Byte Bit7 STDS75 Reserved Default 0 Keys: SD =Shutdown Control Bit M =Thermostat Mode POL =Output Polarity FT0 =Fault Tolerance0 Bit 1. Indicates Operation mode Comparator mode, and 1 = Interrupt mode (see ...

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... The user can read data from the Temperature Register at any time. When a A/D conversion is completed, the new data is loaded into a comparator buffer to evaluate fault conditions, and will update the Temperature Register if a read cycle is not ongoing. The STDS75 is continuously evaluating fault conditions regardless of READ or WRITE activity on the bus READ is ongoing, the previous temperature will be read ...

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... TLSB =Temperature LSB TD =Temperature Data Note: These are comparable formats to the DS75 and LM75. 3.2 Power-up default conditions The STDS75 always powers up in the following default states: ● Thermostat mode = Comparator Mode ● Polarity = Active-low ● Fault tolerance = 1 fault (i.e., relevant bits set to '0' in the Configuration register) ● ...

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... WRITE operations. This device is called the “master” device. The master device also generates the SCL signal which provides the clock signal for all other devices on the bus. These other devices on the bus are called “slave” devices. The STDS75 is a slave device (see Table 10) ...

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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 address pointer. There are two READ modes: ● ...

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... Most Significant Data Byte ACK ACK by by STDS75 Master Data Byte ACK No ACK by by STDS75 Master , HYS Stop Least Significant Data Byte Cond. No ACK by by Master Master AI12281b ...

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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 and indicates to the addressed device that word address will follow and written to the on-chip address pointer. ...

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... Master Most Significant Data Byte 26/37 WRITE HYS Pointer Byte ACK ACK by STDS75 STDS75 Least Significant Data Byte ACK by STDS75 STDS75 Stop Cond. ACK by by Master AI12284b ...

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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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... These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents. Table 11. ...

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... Table 12. Operating and AC measurement conditions V /V supply voltage DD BAT Ambient operating temperature (T Input rise and fall times Input pulse voltages Input and output timing reference voltages Parameter ) A STDS75 Unit 2.7 to 5.5 V –55 to 125 °C ≤ 0 0 29/37 ...

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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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... DS = MSOP8 (TSSOP8) Temperature range 2 = –55 to 125°C Shipping method F = ECOPACK package, Tape & Reel E=ECOPACK package, Tube 1. Contact ST sales office for availability For other options, or for more information on any aspect of this device, please contact the ST Sales Office nearest you. (1) STDS75 35/37 ...

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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 time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...