ADT7467 Analog Devices, Inc., ADT7467 Datasheet - Page 9

• Manufacturer Part Number: ADT7467
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

PRODUCT DESCRIPTION
The ADT7467 is a complete thermal monitor and multiple fan
controller for systems requiring thermal monitoring and
cooling. The device communicates with the system via a serial
system management bus. The serial bus controller has a serial
data line for reading and writing addresses and data (Pin 16)
and an input line for the serial clock (Pin 1). All control and
programming functions for the ADT7467 are performed over
the serial bus. In addition, a pin can be reconfigured as an
SMBALERT output to signal out-of-limit conditions.
COMPARISON BETWEEN ADT7460 AND ADT7467
The ADT7467 is an upgrade to the ADT7460. The ADT7467
and ADT7460 are almost pin and register map compatible. The
ADT7467 and ADT7460 have the following differences:
1.
2.
3.
4.
On the ADT7467, the PWM drive signals can be config-
ured as either high frequency or low frequency drives. The
low frequency option is programmable between 10 Hz and
100 Hz. The high frequency option is 22.5 kHz. On the
ADT7460, only the low frequency option is available.
Once V
temperature and fan speeds is enabled on the ADT7467. If
V
first SMBus transaction with the ADT7467 is complete. On
the ADT7460, the STRT bit in Configuration Register 1
must be set to enable monitoring.
The fans are switched off by default upon power-up of the
ADT7467. On the ADT7460, the fans run at full speed
upon power-up.
Fail-safe cooling is provided on the ADT7467. If the
measured temperature exceeds the THERM limit
(100°C), the fans run at full speed.
Fail-safe cooling is also provided 4.6 sec after V
up. The fans operate at full speed if the ADT7467 has not
been addressed via the SMBus within 4.6 sec of when the
V
that the SMBus fails. The ADT7467 can be programmed at
any time, and it behaves as programmed. If V
powered up, fail-safe cooling is effectively disabled. If V
is disabled, writing to the ADT7467 at any time causes the
ADT7467 to operate normally.
Series resistance cancellation (SRC) is provided on the
remote temperature channels on the ADT7467, but not on
the ADT7460. SRC automatically cancels linear offset
introduced by a series resistance between the thermal
diode and the sensor.
CCP
CCP
is never powered up, monitoring is enabled when the
is powered up. This protects the system in the event
CC
and V
CCP
are powered up, monitoring of
CCP
CCP
is powered
is never
CCP
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5.
6.
7.
8.
9.
10. A GPIO can also be made available on Pin 9 on the
11. The ADT7460 has three possible SMBus addresses, which
Due to the inclusion of extra functionality, the register map has
changed, including an additional configuration register,
Configuration Register 5 at Address 0x7C.
The ADT7467 has an extended temperature measurement
range. The measurement range goes from–64°C to +191°C.
On the ADT7460, the measurement range is from −127°C
to +127°C. This means that the ADT7467 can measure
higher temperatures. The ADT7467 also includes the
ADT7460 temperature range; the temperature measure-
ment range can be switched by setting Bit 0 of
Configuration Register 5.
The ADT7467 maximum fan speed (% duty cycle) in the
automatic fan speed control loop can be programmed. The
maximum fan speed is 100% duty cycle on the ADT7460
and is not programmable.
The offset register in the ADT7467 is programmable up to
±64°C with 0.50°C resolution. The offset register of the
ADT7460 is programmable up to ±32°C with 0.25°C
resolution.
V
used to set the threshold for THERM ( PROCHOT ) (2/3 of
V
threshold for THERM ( PROCHOT ) is set at V
and V
On the ADT7460, Pin 14 could be reconfigured as
SMBALERT . This is not available on the ADT7467.
SMBALERT can be enabled instead on Pin 9.
ADT7467. This is not available on the ADT7460. Set the
GPIO polarity and direction in Configuration Register 5.
The GPIO status bit is Bit 5 of Status Register 2 (it is shared
with TACH4 and THERM because only one can be enabled
at a time).
are selectable using the address select and address enable
pins. The ADT7467 has one SMBus address available at
Address 0x2E.
CCP
CCP
). 2.5 V is monitored on Pin 14 of the ADT7460. The
is monitored on Pin 14 of the ADT7467 and can be
IL
= 0.8 V on the ADT7460.
ADT7467
IH
= 1.7 V