DS75
2–Wire Thermal Watchdog
www.dalsemi.com
FEATURES
=Temperature
measurements require no
external components
Measures temperatures from –55°C to
+125°C. Fahrenheit equivalent is –67°F to
+257°F.
Thermometer accuracy is
±2.0°C.
Thermometer resolution is configurable from
nine (default) to 12 bits (0.5°C to 0.0625°C
resolution)
9–bit readout mode features a max
conversion time of 150 ms.
Thermostatic settings are user definable.
Data is read from/written via a 2–wire serial
interface. (open drain I/O lines). 3–bit
addressability
Wide power supply range (2.7V – 5.5V).
Applications include personal computers,
cellular telephones, office equipment, or any
thermally sensitive system.
Pin/software compatible to LM75CIM–x
Thermal Watchdog in 9–bit (default) mode.
8–pin 150 mil SOIC package.
PIN ASSIGNMENT
SDA
SCL
O.S.
GND
1
2
3
4
8
7
6
5
V
DD
A
0
A
1
A
2
DS75S
8-PIN SOIC (150 MIL)
PIN DESCRIPTION
SDA
SCL
GND
O.S.
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
DESCRIPTION
The DS75 2–wire thermal watchdog provides 9–bit temperature readings which indicate the temperature
of the device. Thermostat settings and temperature readings are all communicated to/from the DS75 over
a simple 2–wire serial interface. No additional components are required; the device is truly a
“temperature–to–digital” converter.
The DS75 has three address bits that allow a user to multidrop up to eight sensors along the 2–wire bus,
greatly simplifying the bussing of distributed temperature sensing networks.
The open–drain thermal alarm output, O.S., becomes active when the temperature of the device exceeds a
user–defined temperature T
OS
. The number of consecutive faults required to set O.S. active is
configurable by the user. The device can also be configured in the interrupt or comparator mode, to
customize the method which clears the fault condition.
For applications that require greater temperature resolution, the user can adjust the readout resolution
from 9 to 12 bits. This is particularly useful in applications where thermal runaway conditions must be
detected quickly.
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