ADT7475 Analog Devices, Inc., ADT7475 Datasheet - Page 32

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

ADT7475
Y
Y
AFTER THE FAIL-SAFE TIMEOUT
FAIL-SAFE TIMER ELAPSES
ADT7475 IS POWERED UP
START FAIL-SAFE TIMER
HAS THE ADT7475 BEEN
HAS THE ADT7475 BEEN
HAS THE ADT7475 BEEN
SMBus TRANSACTION?
SMBus TRANSACTION?
SMBus TRANSACTION?
ACCESSED BY A VALID
ACCESSED BY A VALID
ACCESSED BY A VALID
IS V
ADT7475 NORMALLY
CCP
START UP THE
ABOVE 0.75V?
N
Y
N
Y
Figure 42.
N
N
HAS THE ADT7475 BEEN
SMBus TRANSACTION?
ACCESSED BY A VALID
SWITCH OFF FANS
RUNS THE FANS
TO FULL SPEED
CHECK V
Y
CCP
Rev. B | Page 32 of 68
N
POWER-ON DEFAULT
When the ADT7475 is powered up, it polls the V
If V
powered up), the ADT7475 assumes the functionality of the
default registers after the ADT7475 is addressed via any valid
SMBus transaction.
If V
up), a fail-safe timer begins to count down. If the ADT7475 is
not addressed by any valid SMBus transactions before the fail-
safe timeout (4.6 seconds) lapses, the ADT7475 drives the fans
to full speed. If the ADT7475 is addressed by a valid SMBus
transaction after this point, the fans stop, and the ADT7475
assumes its default settings and begins normal operation.
If V
up), then a fail-safe timer begins to count down. If the
ADT7475 is addressed by a valid SMBus transaction before the
fail-safe timeout (4.6 seconds) lapses, then the ADT7475
operates normally, assuming the functionality of all the default
registers. See the flow chart in Figure 42.
CCP
CC
CCP
goes high (the system processor power rail is powered
stays below 0.75 V (the system CPU power rail is not
goes high (the system processor power rail is powered
CCP
input.