LM93CIMT National Semiconductor, LM93CIMT Datasheet - Page 30

• Manufacturer Part Number: LM93CIMT
• Description: Microprocessor Support IC
• Manufacturer: National Semiconductor

Specifications of LM93CIMT

• Peak Reflow Compatible (260 C): No
• Supply Voltage Max: 3.6V
• Leaded Process Compatible: No
• Supply Voltage Min: 3V
• Operating Temperature Min: 0��C
• Package / Case: 56-TSSOP
• Operating Temperature Max: 85°C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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15.0 Using The LM93
15.10.2 Fan Control Temperature Resolution
As shown in the example the auto fan control algorithm can
operate in a mode that allows 0.5˚C of temperature resolu-
tion instead of the normal 1˚C. When this mode is enabled,
the temperature offset registers that make up the lookup
table are interpreted differently. One LSB represents 0.5˚C,
and the available range between each datapoint is 0˚C to
In this example: Zones 1 and 2 are bound to the PWM1 output and the PWM1 frequency set to a value in the low range;
Hysteresis is set to 2˚C; Toffset and hysteresis resolution is set to 0.5˚C; minPWM register set to 05h for Zones 1/2. Note,
the duty cycle assignment depends on the zone to PWM output binding and the frequency setting of that PWM output.
In this example: Zone 3 and Zone 4 are bound to the PWM 2 output and the PWM2 output frequency set to 22.5kHz; Hys-
teresis is set to 1˚C; Toffset and hysteresis resolution set to 0.5˚C; minPWM for Zones 3/4 register is set to 06h. Note, the
duty cycle assignment depends on the zone to PWM output binding and the frequency setting of that PWM output.
Duty Cycle
Duty Cycle
Lookup
Lookup
Table
Table
28.57
32.14
35.71
39.29
42.86
46.43
53.57
57.14
71.43
85.71
31.25
43.75
56.25
68.75
81.25
93.75
37.5
62.5
87.5
100
100
(%)
(%)
25
50
25
50
75
Zone 1/2
Zone 3/4
Toffset
Toffset
table
table
(˚C)
(˚C)
0.5
1.5
1.5
1.5
0.5
0.5
0.5
0
0
0
0
0
2
0
1
0
0
0
0
0
0
1
1
1
Ambient
CPU1,
Zone1
Tbase
Tbase
LM93
(˚C)
(˚C)
70
30
Zone 3/4 (LM93 Ambient and External Ambient) Table
(Continued)
CPU1 Thermal Diode, Zone 1
LM93 Ambient, Zone 3 (T
Zone 1/2 (CPU1 and CPU2) Table
(˚C)
(˚C)
70.5
76.5
33.5
34.5
70
72
74
75
78
30
31
32
33
34
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
T
T
(T
≤T
≤T
D
A
D
D
D
D
D
D
A
A
A
A
A
A
D
<
<
D
A
<
<
<
<
<
<
<
<
<
<
<
<
)
30
70
70.5
72
74
75
76.5
78
30
31
32
33
33.5
34
34.5
7.5˚C instead of 0˚C to 15˚C. In addition, the hysteresis
registers for auto fan control are interpreted in the same way
(one LSB equals 0.5˚C).
Zones 1, 2 and 3 all have 9-bits of internal resolution, which
makes this feature useful. Zone 4 is written in from the
SMBus and only has 8-bits of resolution. The LM93 left
justifies the value into a 9-bit field before using it, if the 0.5˚C
mode is enabled.
(˚C)
(˚C)
A
)
External
Ambient
CPU2,
Zone2
Tbase
Tbase
(˚C)
(˚C)
60
35
External Ambient, Zone 4 (T
CPU2 Thermal Diode, Zone 2
(˚C)
(˚C)
60.5
66.5
38.5
39.5
60
62
64
65
68
35
36
37
38
39
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
≤T
T
T
≤T
≤T
(T
D
A
D
D
D
D
D
D
A
A
A
A
A
A
<
<
D
D
A
<
<
<
<
<
<
<
<
<
<
<
<
)
60
60.5
62
64
65
66.5
68
35
36
37
38
38.5
39
39.5
(˚C)
(˚C)
A
)