LM95172

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SNOSB33B – DECEMBER 2009 – REVISED MARCH 2013

Power-Up Sequence

WARNING

minimum operating voltage must be reached in 5 ms or less.

voltage-vs.-time function is as a typical R-C Charging exponential function the time constant must be less

than or equal to 1.25 ms.

another function the following requirements must be met:

time before the specified minimum operating voltage is reached.

allowed to drop below the specified minimum operating voltage at any time after the specified minimum

operating voltage is reached.

Power On Reset (POR)

After the requirements of Software Reset Sequence and Power-Up Sequence are met each register will then

contain its defined POR default value. Any of the following actions may cause register values to change from

their POR value:

1. The master writes different data to any Read/Write (R/W) bits, or

2. The LM95172EWG is powered down.

The specific POR Value of each register is listed in INTERNAL REGISTER STRUCTURE.

ONE SHOT CONVERSION

The LM95172EWG features a one-shot conversion bit, which is used to initiate a singe conversion and

comparison cycle when the LM95172EWG is in shutdown mode. While the LM95172EWG is in shutdown mode,

writing a "1" to the One-Shot bit in the Control/Status Register will cause the LM95172EWG to perform a single

temperature conversion and update the Temperature Register and the affected status bits. Operating the

LM95172EWG 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 LM95172EWG initiates a temperature conversion. After this initiation, but

before the completion of the conversion, and resultant register updates, the LM95172EWG 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). All other registers contain the data that was present before initiating

the one-shot conversion. After the temperature measurement is complete, the DAV flag will be set to "1" and the

temperature register will contain the resultant measured temperature.

OVERTEMP OUTPUT

The Over-temperature (OVERTEMP) output is a temperature switch signal that indicates when the measured

the OVERTEMP output resets. The OVERTEMP output of the LM95172EWG behaves as a temperature

comparator. The following explains the operation of OVERTEMP. Figure 10 illustrates the OVERTEMP output

behavior.

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