DS1621 Datasheet, PDF (1/16 Pages) Dallas Semiconductor – Digital Thermometer and Thermostat

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DS1621
Digital Thermometer and Thermostat
FEATURES
§ Temperature measurements require no
external components
§ Measures temperatures from –55°C to
+125°C in 0.5°C increments. Fahrenheit
equivalent is –67°F to 257°F in 0.9°F
increments
§ Temperature is read as a 9–bit value (2-
byte transfer)
§ Wide power supply range (2.7V to 5.5V)
§ Converts temperature to digital word in 1
second
§ Thermostatic settings are user definable
and nonvolatile
§ Data is read from/written via a two–wire
serial interface (open drain I/O lines)
§ Applications include thermostatic
controls, industrial systems, consumer
products, thermometers, or any thermal
sensitive system
§ 8–pin DIP or SOIC package (150-MIL and
208-MIL)
PIN ASSIGNMENT
SDA
1
8
V_DD
SCL
2
T_OUT
3
7
A₀
6
A₁
GND
4
5
A₂
DS1621S 8-PIN SOIC (150-MIL)
DS1621V 8-PIN SOIC (208-MIL)
See Mech Drawings Section
SDA 1
8
V_DD
SCL
2
7
A₀
T_OUT
3
6
A₁
GND
4
5
A₂
DS1621 8-PIN DIP (300-MIL)
See Mech Drawings Section
PIN DESCRIPTION
SDA
- 2-Wire Serial Data Input/Output
SCL
- 2-Wire Serial Clock
GND
- Ground
T_OUT
A0
- Thermostat Output Signal
- Chip Address Input
A1
- Chip Address Input
A2
- Chip Address Input
V_DD
- Power Supply Voltage
DESCRIPTION
The DS1621 Digital Thermometer and Thermostat provides 9–bit temperature readings which indicate
the temperature of the device. The thermal alarm output, T_OUT, is active when the temperature of the
device exceeds a user–defined temperature TH. The output remains active until the temperature drops
below user defined temperature TL, allowing for any hysteresis necessary.
User-defined temperature settings are stored in nonvolatile memory so parts may be programmed prior to
insertion in a system. Temperature settings and temperature readings are all communicated to/from the
DS1621 over a simple two–wire serial interface.
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