lm96080cimt National Semiconductor Corporation, lm96080cimt Datasheet - Page 17

• Manufacturer Part Number: lm96080cimt
• Description: System Hardware Monitor With 2-wire Serial Interface
• Manufacturer: National Semiconductor Corporation

Divide by 1
Divide by 2
Divide by 4
Divide by 8
Mode Select
The table below shows example calculation for Count with
different divisor and frequency. Counts are based on 2 pulses
per revolution tachometer outputs.
RPM
4400
3080
2640
Nominal RPM
8800
4400
2200
1100
(d) Fan with Strong Tach Pull-Up or Totem Pole Output and Diode Clamp
Time per Revolution
13.64 ms
19.48 ms
22.73 ms
Time per Revolution
(c) Fan with Tach Pull-Up to +12V and Diode Clamp
13.64 ms
27.27 ms
54.54 ms
6.82 ms
FIGURE 5. Alternatives for Fan Inputs
Given Speed in Decimal
17
Counts for “Divide by 2”
Counts for the
(Default) in Decimal
(maximum counts)
153
153
153
153
153 counts
219 counts
255 counts
30070114
30070115
70% RPM
6160
3080
1540
770
Time per Revolution
Typical RPM
for 70% RPM
Comments
70% RPM
60% RPM
19.48 ms
38.96 ms
77.92 ms
9.74 ms
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