LM95172QA2MDA NSC [National Semiconductor], LM95172QA2MDA Datasheet - Page 11

• Manufacturer Part Number: LM95172QA2MDA
• Manufacturer: NSC [National Semiconductor]

1.2 ONE SHOT CONVERSION
The LM95172Q features a one-shot conversion bit, which is
used to initiate a singe conversion and comparison cycle
when the LM95172Q is in shutdown mode. While the
LM95172Q is in shutdown mode, writing a "1" to the One-Shot
bit in the Control/Status Register will cause the LM95172Q to
perform a single temperature conversion and update the
Temperature Register and the affected status bits. Operating
the LM95172Q in this one-shot mode allows for extremely low
average-power comsumption, making it ideal for low-power
applications.
When the One-shot bit is set, the LM95172Q initiates a tem-
perature conversion. After this initiation, but before the com-
pletion of the conversion, and resultant register updates, the
LM95172Q is in a "one-shot" state. During this state, the Data
Available (DAV) flag in the Control/Status Register is "0" and
the Temperature Register contains the value 8000h (-256°C).
The OVERTEMP Output will assert when the measured tem-
perature is greater than the T
reset if any of the following events happens:
1. The temperature falls below the value stored in the T
register, or
2. A "1" is written to the OVERTEMP Reset bit in the Control/
Status Register.
FIGURE 9. LM95172Q OVERTEMP vs. Temperature Response Diagram
HIGH
value. OVERTEMP will
LOW
11
All other registers contain the data that was present before
initiating the one-shot conversion. After the temperature mea-
surement is complete, the DAV flag will be set to "1" and the
temperature register will contain the resultant measured tem-
perature.
1.3 OVERTEMP OUTPUT
The Over-temperature (OVERTEMP) output is a temperature
switch signal that indicates when the measured temperature
exceeds the T
T
register is used to set the hysteresis. The T
sets the temperature below which the OVERTEMP output re-
sets. The OVERTEMP output of the LM95172Q behaves as
a temperature comparator. The following explains the opera-
tion of OVERTEMP. Figure 9 illustrates the OVERTEMP
output behavior.
If OVERTEMP is cleared by the master writing a "1" to the
OVERTEMP Reset bit while the measured temperature still
exceeds the T
the completion of the next temperature conversion. Placing
the LM95172Q in shutdown mode or triggering a one-shot
conversion does not cause OVERTEMP to reset.
HIGH
register sets the high temperature limit and the T
HIGH
HIGH
value, OVERTEMP will assert again after
programmed limit. The programmable
30035721
LOW
register also
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LOW