ADT7473 Analog Devices, Inc., ADT7473 Datasheet - Page 45

• Manufacturer Part Number: ADT7473
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

STEP 8: T
T
temperature measured has dropped back below T
fan turns off. The premise for temperature hysteresis (T
that, without it, the fan would merely chatter or cycle on a
regularly whenever temperature is hovering at about the T
setting.
The T
for the system to cool down or heat up as the fan turns on and
off. Values of hysteresis are programmable in the range 1°C to
15°C. Larger values of T
and off. The T
The T
for fan on/off, but the same setting is used for the T
hysteresis value, described in Step 6: T
Channels. Therefore, programming Register 0x6D and Register
0x6E sets the hysteresis for both fan on/off and the THERM
function.
HYST
is the amount of extra co
HYST
HYST
value chosen determines the amount of time needed
setting applies not only to the temperature hysteresis
H
YST
AMBIENT TEMP
HYS
FOR TEMPERATURE CHANNELS
REMOTE 2 =
REMOTE 1 =
T
VRM TEMP
CPU TEMP
default value is set at 4°C.
LOCAL =
100%
0%
HYST
prevent the fans from chattering
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
oling a fan provides after the
T
T
T
T
MIN
MIN
MIN
MIN
RANGE
T
RANGE
for Temperature
T
T
T
RANGE
RANGE
RANGE
Figure 59. How T
T
100%
100%
100%
THERM
MIN
0%
0%
0%
THERM
before the
HYST
MUX
nd off
MIN
) is
THERM
Rev. A | Page 45 of 76
on
Rela
tes to Automa
PWM
PW
PWM
MIN
MI
MIN
Hysteresis Registers
Register 0x6D, Remote 1, Local Hysteresis Register
Bits [7:4] Remote 1 temperature hysteresis (4°C default)
Bits [3:0] Local temperature hysteresis (4°C default)
Register 0x6E, Remote 2 Temperature Hysteresis Register
Bits [7:4], Remote 2 temperature hysteresis (4°C default)
In some applications, it is required that fans not turn off below
T
Acoustics Register 1 (0x62) allow the fans to be turned off or to
be kept spinning below T
value has no effect on the fan when the temperature drops
below T
N
M
MIN
ENHANCEMENT)
ENHANCEMENT)
MEASUREMENT
MEASUREMENT
ENHANCEMENT)
, but remain running at PWM
TACHOMETER 1
TACHOMETER 2
TACHOMETER 3
MEASUREMENT
tic Fan Control
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
MIN
RAMP
RAMP
RAMP
AND 4
.
GENERATOR
GENERATOR
GENERATOR
CONFIG
CONFIG
CO
PWM
PWM
PWM
PWM
PWM
PWM
NFIG
MIN
. If the fans are always on, the T
MIN
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
. Bits [7:5] of the Enhance
FRONT CHASSIS
REAR CHASSIS
CPU F
AN SINK
ADT7473
HYST