Datasheet

LM96000
SNAS234C –APRIL 2004–REVISED MARCH 2013 www.ti.com
Example for PWM1 assigned to Zone 1:
• – Zone 1 Fan Temp Limit (Register 67h) is set to 50°C (32h).
• – Range (Register 5Fh) is set to 8°C (6xh).
• – Fan 1 PWM Minimum (Register 64h) is set to 50% (32h).
In this case, the PWM1 duty cycle will be 50% at 50°C.
Since (Zone 1 Fan Temp Limit) + (Zone 1 Range) = 50°C + 8°C = 58°C, the fan will run at 100% duty cycle when
the temperature of the Zone 1 sensor reaches 58°C.
Since the midpoint of the fan control range is 54°C, and the median duty cycle is 75% (Halfway between the
PWM Minimum and 100%), PWM1 duty cycle would be 75% at 54°C.
Above (Zone 1 Fan Temp Limit) + (Zone 1 Range), the duty cycle will be 100%.
PWM frequency bits [3:0]
The PWM frequency bits [3:0] determine the PWM frequency for the fan.The LM96000 has high and low
frequency ranges for the PWM outputs, that are controlled by the HLFRQ bit.
PWM Frequency Selection (Default = 0011 = 30.04 Hz).
Table 6. Register Setting vs PWM Frequency
HLFRQ Freq [2:0] PWM Frequency
0 000 10.01 Hz
0 001 15.02 Hz
0 010 23.14 Hz
0 011 30.04 Hz
0 100 38.16 Hz
0 101 47.06 Hz
0 110 61.38 Hz
0 111 94.12 Hz
1 000 22.5 kHz
1 001 24 kHz
1 010 25.7 kHz
1 011 25.7 kHz
1 100 27.7 kHz
1 101 27.7 kHz
1 110 30 kHz
1 111 30 kHz
Range Selection RAN [3:0]
RAN [3:0] Range (°C)
0000 2
0001 2.5
0010 3.33
0011 4
0100 5
0101 6.67
0110 8
0111 10
1000 13.33
1001 16
1010 20
1011 26.67
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