FM75_06 FAIRCHILD [Fairchild Semiconductor], FM75_06 Datasheet - Page 7

• Manufacturer Part Number: FM75_06
• Description: Low-Voltage Two-Wire Digital Temperature Sensor with Thermal Alarm
• Manufacturer: FAIRCHILD [Fairchild Semiconductor]

© 2006 Fairchild Semiconductor Corporation
FM75 Rev. 1.0.8
Comparator Mode
In comparator mode, each time a temperature-to-digital
(T-to-D) temperature conversion occurs, the new digital
temperature is compared to the value stored in the T
and T
secutive temperature measurements are greater than
the value stored in the T
vated. For example, if bits F1 and F0 are equal to “10”
(fault tolerance = 4), four consecutive temperature mea-
surements must exceed T
Once the OS output is active, it remains active until the
first time the measured temperature drops below the
temperature stored in the T
of the alarm in comparator mode with fault tolerance = 2
is illustrated in Figure 4.
HYST
registers. If a fault tolerance number of con-
OS (Comparator Mode)
Temperature-to-Digital
OS (Interrupt Mode)
Figure 4. Thermal Alarm Operation in Comparator and Interrupt Modes
OS
OS
register, the OS output is acti-
HYST
Conversion
to activate the OS output.
T
register. The operation
T
HYST
OS
For this example:
Fault Tolerance = 2
Output Polarity = Active Low
OS
7
Interrupt Mode
In interrupt mode, the OS output first becomes active
after a fault tolerance number of consecutive tempera-
ture measurements exceed the value stored in the T
register (similar to comparator mode). Once OS is active,
it can only be cleared by a user read from any of the
FM75 registers (temperature, configuration, T
T
by setting the shutdown bit in the configuration register to
“1”). Once cleared, the OS output can only be activated
the next time by a fault tolerance number of consecutive
temperature measurements lower than the value stored
in T
deactivated by a user read or shutdown. In interrupt
mode, the activate/clear cycle for OS has the following
pattern: temperature > T
clear, temperature > T
alarm in interrupt mode with fault tolerance = 2 is illus-
trated in Figure 4.
HYST
HYST
) or by putting the FM75 into shutdown mode (i.e.,
. Once it is activated, the OS output can only be
Read (or Shutdown)
OS
OS
, clear, etc. The operation of the
, clear, temperature < T
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OS
HYST
, or
OS
,