Rainbow Electronics DS1621 - Manual

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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
PIN DESCRIPTION
SDA - 2-Wire Serial Data Input/Output
SCL - 2-Wire Serial Clock
GND - Ground
T
OUT
- Thermostat Output Signal
A0 - 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.
DS1621
Digital Thermometer and Thermostat
www.dalsemi.com
6 3
1
2
4
8
7
5
SDA
T
OUT
GND
V
DD
A
0
A
1
A
2
DS1621S 8-PIN SOIC (150-MIL)
DS1621V 8-PIN SOIC (208-MIL)
See Mech Drawings Section
6 3
1
2
4
8
7
5
SDA
SCL
T
OUT
GND
V
DD
A
0
A
1
A
2
DS1621 8-PIN DIP (300-MIL)
See Mech Drawings Section
SCL