DS1722 Datasheet, PDF (1/13 Pages) Dallas Semiconductor – Digital Thermometer with SPI/3-Wire Interface

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PRELIMINARY
PRELIMINARY
DS1722
Digital Thermometer with
SPI/3-Wire Interface
FEATURES
Temperature measurements require no
external components
Measures temperatures from -55°C to
+120°C. Fahrenheit equivalent is -67°F to
+248°F
Thermometer accuracy is ±2.0°C
Thermometer resolution is configurable from
8 to 12 bits (1.0°C to 0.0625°C resolution)
Data is read from/written to via a Motorola
Serial Peripheral Interface (SPI) or standard
3-wire serial interface
Wide analog power supply range (2.65V -
5.5V)
Separate digital supply allows for 1.8V logic
Available in an 8-pin SOIC (150 mil), 8-pin
uSOP, and flip chip package
PIN ASSIGNMENT
VDDD
1
8
VDDA
VDDD
1*
8
VDDA
CE
2
7
SERMODE _CE
2
7 _SERMODE
SCLK
3
6
SDI
SCLK ³
6 _SDI
GND
4
5
SDO
GND ⁴
5 _SDO
DS1722S
8-Pin SOIC (150-mil)
DS1722U
8-PIN µ-SOP
PIN DESCRIPTION
SERMODE
- Serial Interface Mode
CE
- Chip Enable
SCLK
- Serial Clock
GND
- Ground
V_DDA
SDO
- Analog Supply Voltage
- Serial Data Out
SDI
- Serial Data In
V_DDD
- Digital Supply Voltage
DESCRIPTION
The DS1722 Digital Thermometer and Thermostat with SPI/3-Wire Interface provides temperature
readings which indicate the temperature of the device. No additional components are required; the device
is truly a temperature-to-digital converter. Temperature readings are communicated from the DS1722
over a Motorola SPI interface or a standard 3-wire serial interface. The choice of interface standard is
selectable by the user.
For applications that require greater temperature resolution, the user can adjust the readout resolution
from 8 to 12 bits. 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.
Applications for the DS1722 include personal computers/servers/workstations, cellular telephones, office
equipment, or any thermally-sensitive system.
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