AVAILAB
LE
DS1621
Digital Thermometer and Thermostat
FEATURES
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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 less
than 1 second
Thermostatic settings are user definable and
nonvolatile
Data is read from/written via a 2-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 SO package (150mil and
208mil)
PIN ASSIGNMENT
SDA
SCL
T
OUT
GND
1
2
3
4
8
7
6
5
V
DD
A
0
A
1
A
2
DS1621S 8-PIN SO (150mil)
DS1621V 8-PIN SO (208mil)
SDA
SCL
T
OUT
GND
1
2
3
4
8
7
6
5
V
DD
A
0
A
1
A
2
DS1621 8-PIN DIP (300mil)
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PIN DESCRIPTION
SDA
SCL
GND
T
OUT
A0
A1
A2
V
DD
- 2-Wire Serial Data Input/Output
- 2-Wire Serial Clock
- Ground
- Thermostat Output Signal
- Chip Address Input
- Chip Address Input
- Chip Address Input
- Power Supply Voltage
Functional Diagrams
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
Pin Configurations appear at end of data sheet.
DS1621 over a simple 2-wire serial
data sheet.
Functional Diagrams continued at end of
interface.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
090905
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
