ADT7475 Analog Devices, Inc., ADT7475 Datasheet - Page 57

• Manufacturer Part Number: ADT7475
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

Table 34. Register 0x62—Enhanced Acoustics Register 1 (Power-On Default = 0x00)
Bit
[2:0]
[3]
[4]
[5]
[6]
[7]
1
This register becomes read-only when the Configuration Register 1 lock bit is set to 1. Any subsequent attempts to write to this register fail.
Name
ACOU1
EN1
SYNC
MIN1
MIN2
MIN3
R/W
R/W
R/W
R/W
R/W
R/W
R/W
1
Description
Assuming that PWMx is associated with the Remote 1 temperature channel, these bits define the maximum
rate of change of the PWMx output for Remote 1 temperature related changes. Instead of the fan speed
jumping instantaneously to its newly determined speed, it ramps gracefully at the rate determined by
these bits. This feature ultimately enhances the acoustics of the fan.
When Bit 7 of Configuration Register 6 (0x10) is 0
Time Slot Increase
000 = 1
001 = 2
010 = 3
011 = 4
100 = 8
101 = 12
110 = 24
111 = 48
When Bit 7 of Configuration Register 6 (0x10) is 1
Time Slot Increase
000 = 1
001 = 2
010 = 3
011 = 4
100 = 8
101 = 12
110 = 24
111 = 48
When this bit is 1, smoothing is enabled on the Remote 1 temperature channel.
SYNC = 1 synchronizes fan speed measurements on TACH2, TACH3, and TACH4 to PWM3. This allows up to
three fans to be driven from PWM3 output and their speeds to be measured.
SYNC = 0 synchronizes only TACH3 and TACH4 to PWM3 output.
When the ADT7475 is in automatic fan control mode, this bit defines whether PWM1 is off (0% duty cycle)
or at PWM1 minimum duty cycle when the controlling temperature is below its T
0 = 0% duty cycle below T
1 = PWM1 minimum duty cycle below T
When the ADT7475 is in automatic fan speed control mode, this bit defines whether PWM2 is off (0% duty
cycle) or at PWM2 minimum duty cycle when the controlling temperature is below its T
value.
0 = 0% duty cycle below T
1 = PWM 2 minimum duty cycle below T
When the ADT7475 is in automatic fan speed control mode, this bit defines whether PWM3 is off (0% duty
cycle) or at PWM3 minimum duty cycle when the controlling temperature is below its T
value.
0 = 0% duty cycle below T
1 = PWM3 minimum duty cycle below T
MIN
MIN
MIN
Time for 0% to 100%
37.5 sec
18.8 sec
12.5 sec
7.5 sec
4.7 sec
3.1 sec
1.6 sec
0.8 sec
Time for 0% to 100%
52.2 sec
26.1 sec
17.4 sec
10.4 sec
6.5 sec
4.4 sec
2.2 sec
1.1 sec
– hysteresis.
– hysteresis.
– hysteresis.
Rev. B | Page 57 of 68
MIN
MIN
MIN
– hysteresis.
– hysteresis.
– hysteresis.
MIN
– hysteresis value.
MIN
MIN
– hysteresis
– hysteresis
ADT7475