lm99-1cimm National Semiconductor Corporation, lm99-1cimm Datasheet - Page 13

• Manufacturer Part Number: lm99-1cimm
• Description: ?1?c Accurate, High Temperature, Remote Diode Temperature Sensor With Two-wire Interface
• Manufacturer: National Semiconductor Corporation

1.0 Functional Description
1.11 DIGITAL FILTER
In order to suppress erroneous remote temperature readings
due to noise, the LM99 incorporates a user-configured digital
FIGURE 9. Digital Filter Response in a Pentium 4 processor System. The filter on and off curves were purposely
D2
0
0
1
1
a) Step Response
D1
0
1
0
1
FIGURE 8. Filter Output Response to a Step Input
offset to better show noise performance.
No Filter
Level 1
Level 1
Level 2
Filter
(Continued)
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filter. The filter is accessed in the FILTER and ALERT CON-
FIGURE REGISTER at BFh. The filter can be set according
to the table shown.
Level 2 sets maximum filtering.
Figure 8 depict the filter output to in response to a step input
and an impulse input. Figure 9 depicts the digital filter in use
in a Pentium 4 processor system. Note that the two curves,
with filter and without, have been purposely offset so that
both responses can be clearly seen. Inserting the filter does
not induce an offset as shown.
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b) Impulse Response
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