LM95234_07 NSC [National Semiconductor], LM95234_07 Datasheet - Page 12

• Manufacturer Part Number: LM95234_07
• Description: Quad Remote Diode and Local Temperature Sensor with SMBus Interface and TruTherm Technology
• Manufacturer: NSC [National Semiconductor]

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processor on a 65 nm or 90 nm process. The filter curves
Figure 3 shows the filter in use in a typical Intel processor on
a 65/90 nm process system. Note that the two curves have
been purposely offset for clarity. Inserting the filter does not
induce an offset as shown.
1.5 FAULT QUEUE
In order to suppress erroneous TCRIT1,TCRIT2 and
TCRIT3 triggering the LM95234 incorporates a Fault Queue
for the unfiltered remote channels 3 and 4. The Fault Queue
acts to ensure the remote temperature measurement of these
channels is genuinely beyond the corresponding Tcrit limit by
not triggering until three consecutive out of limit measure-
ments have been made, see Figure 4 for an example. The
Fault Queue defaults on upon power-up. The fault queue for
channels 3 and 4 can be turned ON or OFF via bits 0 and 1
of the Configuration Register. When the fault queue is en-
abled, the TCRIT1, TCRIT2 and TCRIT3 pins will be triggered
if the temperature is above the Tcrit limit for 3 consecutive
conversions and the corresponding mask bit is 0 in the TCRIT
Mask registers. Similarly the temperature needs to be below
the Tcrit limit minus the hysteresis value for three consecutive
a) Seventeen and fifty degree step
FIGURE 3. Digital Filter Response in a typical Intel
were purposely offset for clarity.
response
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FIGURE 2. Filter Impulse and Step Response Curves
b) Impulse response with input
20106328
transients less than 4°C
12
conversions for the TCRIT1, TRCIT2 and TCRIT3 pins to de-
activate.
1.6 TEMPERATURE DATA FORMAT
Temperature data can only be read from the Local and Re-
mote Temperature value registers. The data format for all
temperature values is left justified 16-bit word available in two
8-bit registers. Unused bits will always report "0". All temper-
ature data is clamped and will not roll over when a tempera-
ture exceeds full-scale value.
Remote temperature data for all channels can be represented
by an 11-bit, two's complement word or unsigned binary word
with an LSb (Least Significant Bit) equal to 0.125°C.
FIGURE 4. Fault Queue Response Diagram (with 0°C
Temperature
+125°C
+25°C
11-bit, 2's Complement (10-bit plus sign)
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0111 1101 0000 0000
0001 1001 0000 0000
c) Impulse response with input
hysteresis)
transients great than 4°C
Binary
Digital Output
7D00h
1900h
Hex
20106327
20106329