DS1722 Dallas, DS1722 Datasheet
DS1722
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DS1722 Summary of contents
Page 1
... This is particularly useful in applications where thermal runaway conditions must be detected quickly. For application flexibility, the DS1722 features a wide analog supply rail of 2.65V - 5.5V. A separate digital supply allows a range of 1.8V to 5.5V. The DS1722 is available in an 8-pin SOIC (150-mil), 8-pin uSOP, and flip chip package. ...
Page 2
... V Analog Supply Voltage 2.65V – 5.5V input power pin. PIN 8 DDA OVERVIEW A block diagram of the DS1722 is shown in Figure 1. The DS1722 consists of four major components: 1. Precision temperature sensor 2. Analog-to-digital converter 3. SPI/3-wire interface electronics 4. Data registers The factory-calibrated temperature sensor requires no external components. The DS1722 power- conserving shutdown state upon power-up ...
Page 3
... C. The device powers power-conserving shutdown mode. After power-up, the DS1722 may be placed in a continuous conversion mode one-shot conversion mode. In the continuous conversion mode, the device continuously computes the temperature and stores the most recent result in the temperature register at addresses 01h (LSB) and 02h (MSB) ...
Page 4
... SPI or 3-wire interface with the address set to the temperature register, 01h (LSB) and then 02h (MSB). Table 2 describes the exact relationship of output data to measured temperature. The table assumes the DS1722 is configured for 12-bit resolution; if the device is configured in a lower resolution mode, those bits will contain 0s. The data is transmitted serially over the digital interface, MSb first for SPI communication and LSb first for 3-wire communication. The MSb of the temperature register contains the “ ...
Page 5
... MSb 1SHOT = One-shot temperature conversion bit. conversions are not taking place), a "1" written to the 1SHOT bit will cause the DS1722 to perform one temperature conversion and store the results in the temperature register at addresses 01h (LSB) and 02h (MSB). The bit will clear itself to "0" upon completion of the temperature conversion. The user has read/write access to the 1SHOT bit, although writes to this bit will be ignored if the SD bit is a " ...
Page 6
... The SDI and SDO pins are the serial data input and output pins for the DS1722, respectively. The CE input is used to initiate and terminate a data transfer. The SCLK pin is used to synchronize data movement between the master (microcontroller) and the slave (DS1722) devices. ...
Page 7
... Data transfers can occur 1 byte at a time in multiple-byte burst mode. After CE is driven high an address is written to the DS1722. After the address, one or more data bytes can be written or read. For a single- byte transfer, 1 byte is read or written and then CE is driven low (see Figures 4 and 5). For a multiple- byte transfer, however, multiple bytes can be read or written to the DS1722 after the address has been written (see Figure 6) ...
Page 8
... Figure 7 illustrates a read and write cycle. Figure 8 illustrates a multiple byte burst transfer. In 3-wire mode, data is input on the rising edge of SCLK and output on the falling edge of SCLK. 3-WIRE SINGLE BYTE TRANSFER Figure 7 3-WIRE MULTIPLE BYTE BURST TRANSFER Figure DS1722 ...
Page 9
... Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. The Dallas Semiconductor DS1722 is built to the highest quality standards and manufactured for long term reliability. All Dallas Semiconductor devices are made using the same quality materials and manufacturing methods ...
Page 10
... TYP MAX UNITS NOTES 2 bits 67 125 150 250 300 500 600 1000 1200 DD MIN TYP MAX UNITS NOTES 100 ns 100 ns DC 5.0 MHz 200 ns 400 ns 100 ns 400 DS1722 = = = = 5.5V =5.5V ...
Page 11
... C to +120 C, 2.65V = = = = V CONDITION MIN CDH t CDD CLK CCH t CWH t CDZ TYP MAX UNITS 100 ns 100 ns DC 5.0 MHz 200 ns 400 ns 100 ns 400 DS1722 = = = = 5.5V) NOTES ...
Page 12
... Figure 13 shows mean thermometer error for a pre-characterization sample. Data covering a larger sample over the full temperature range is pending. and CE=GND. Typical I DDD or V =0.2 V and 10 ms maximum rise and fall time. IL DDD Measured from the 50% point of SCLK to the V OL DDD 0.25 µA and 25°C CC1 CC DS1722 OH ...
Page 13
... TYPICAL DS1722 THERMOMETER ERROR DS1722 ...