Datasheet

10 100 1000 10000
CONVERSION TIME (ms)
0.0
0.25
0.5
0.75
1.0
1.25
1.5
1.75
2.0
AVERAGE I
DD
(mA)
V
DD
= +3.3V
T
A
= 25
o
C
LM95231
SNIS139E –FEBRUARY 2005–REVISED MARCH 2013 www.ti.com
CONVERSION SEQUENCE
In the power up default state the LM95231 takes maximum a 77.5 ms to convert the Local Temperature, Remote
Temperature 1 and 2, and to update all of its registers. Only during the conversion process is the busy bit (D7) in
the Status register (02h) high. These conversions are addressed in a round robin sequence. The conversion rate
may be modified by the Conversion Rate bits found in the Configuration Register (03h). When the conversion
rate is modified a delay is inserted between conversions, the actual maximum conversion time remains at 87.7
ms. Different conversion rates will cause the LM95231 to draw different amounts of supply current as shown in
Figure 6.
Figure 6. Conversion Rate Effect on Power Supply Current
POWER-ON-DEFAULT STATES
LM95231 always powers up to these known default states. The LM95231 remains in these states until after the
first conversion.
1. Command Register set to 00h
2. Local Temperature set to 0°C until the end of the first conversion
3. Remote Diode Temperature set to 0°C until the end of the first conversion
4. Remote Diode digital filters are on.
5. Remote Diode 1 model is set to Pentium 4 processor on 90nm process with TruTherm mode enabled.
Remote Diode 2 model is set to 2N3904 with TruTherm mode disabled.
6. Status Register depends on state of thermal diode inputs
7. Configuration register set to 00h; continuous conversion, typical time = 85.8 ms when TruTherm Mode is
enabled for Remote 1 only
SMBus INTERFACE
The LM95231 operates as a slave on the SMBus, so the SMBCLK line is an input and the SMBDAT line is
bidirectional. The LM95231 never drives the SMBCLK line and it does not support clock stretching. According to
SMBus specifications, the LM95231 has a 7-bit slave address. All bits A6 through A0 are internally programmed
and can not be changed by software or hardware. The SMBus slave address is dependent on the LM95231 part
number ordered:
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