EMC6D103-CK SMSC [SMSC Corporation], EMC6D103-CK Datasheet - Page 46

• Manufacturer Part Number: EMC6D103-CK
• Description: FAN CONTROL DEVICE WITH HIGH FREQUENCY PWM
• Manufacturer: SMSC [SMSC Corporation]

Revision 0.4 (04-04-05)
7.1.4.8
FREQUENCY
FREQUENCY
PWM
PWM
(HZ)
(HZ)
87.7
58.6
35.2
29.3
21.9
14.6
87.7
58.6
35.2
29.3
44
44
11
Note 7.1
Examples of Minimum RPMs Supported
The following tables show minimum RPMs that can be supported with the different parameters. The
first table uses 3 edges and the second table uses 2 edges.
Note 7.2
Note 7.3
(MSEC)
(MSEC)
11.42
17.12
22.73
25%
2.85
4.27
5.68
8.53
25%
2.85
4.27
5.68
8.53
PULSE WIDTH AT DUTY CYCLE
7.1
PULSE WIDTH AT DUTY CYCLE
7.1
This max value will be FFFFh if the programmed number of edges is detected when the
count reaches FFFFh or if no edges are detected. If the count reaches FFFFh in Mode 1
and some edges were detected, but less than the programmed number of edges, the
maximum tach count value is determined by the Slow Interrupt Enable bit located in the
TACHx Options registers at offsets 90h to 93h. If slow interrupt detection is set to 0, the
count will be forced to FFFEh, else the count will be forced to FFFFh.
100% duty cycle is 255/256.
RPM=60/T
(PWM ”ON” Time – Guard Time). Minimum RPM values shown use minimum guard time
(88.88usec).
Table 7.2 Minimum RPM Detectable Using 3 Edges
Table 7.3 Minimum RPM Detectable Using 2 Edges
(PWM ”ON” TIME)
(PWM ”ON” TIME)
(MSEC)
Fan Control Device with High Frequency PWM Support and Hardware Monitoring Features
(MSEC)
11.36
17.06
22.83
34.25
45.45
Revolution
50%
8.53
14.2
17.06
11.36
5.7
50%
8.53
14.2
5.7
, T
TachPulse
DATASHEET
(Note
(Note
(MSEC)
(MSEC)
100%
11.36
22.64
45.48
68.23
90.55
28.3
100%
22.64
11.36
17
34
28.3
17
34
7.2)
= T
46
7.4)
Revolution
MINIMUM RPM AT DUTY CYCLE
MINIMUM RPM AT DUTY CYCLE
10865
7175
5366
4279
3554
2648
1761
1325
/2. Using 3 edges for detection, T
25%
5433
3588
2683
2139
1777
25%
(30/T
(30/T
5347
3554
2662
2126
1768
1319
50%
878
661
2673
1777
1331
1063
50%
TachPulse
TachPulse
884
)
)
SMSC EMC6D103
(Note
(Note
100%
2662
1774
1330
1063
885
661
440
332
100%
1331
TachPulse
887
665
532
442
Datasheet
7.3)
7.5)
=