ADT7473_11 ONSEMI [ON Semiconductor], ADT7473_11 Datasheet - Page 67

• Manufacturer Part Number: ADT7473_11
• Description: dbCOOL Remote Thermal Monitor and Fan Control
• Manufacturer: ONSEMI [ON Semiconductor]

Table 41. THERM Limit Registers
1. If any temperature measured exceeds its THERM limit, all PWM outputs drive their fans at 100% duty cycle. This is a fail−safe mechanism
2. These registers become read−only when the Configuration Register 1 lock bit is set to 1. Any further attempts to write to these registers
Table 42. Temperature/T
1. Each 4−bit value controls the amount of temperature hysteresis applied to a particular temperature channel. Once the temperature for
2. These registers become read−only when the Configuration Register 1 lock bit is set to 1. Any further attempts to write to these registers
Table 43. XNOR Tree Test Register
Register Address
1. These registers become read−only when the Configuration Register 1 lock bit is set to 1. Any further attempts to write to these registers
Table 44. Remote 1 Temperature Offset Register (0x70)
1. This register becomes read−only when the Configuration Register 1 lock bit is set to 1. Any further attempts to write to this register have
Register Address
Register Address
Register Address
incorporated to cool the system in the event of a critical overtemperature. It also ensures some level of cooling in the event that software
or hardware locks up. If set to 0x80, this feature is disabled. The PWM output remains at 100% until the temperature drops below THERM
Limit − Hysteresis. If the THERM pin is programmed as an output, then exceeding these limits by 0.25°C can cause the THERM pin to
assert low as an output.
have no effect.
that channel falls below its T
15°C of hysteresis can be assigned to any temperature channel. The hysteresis value chosen also applies to that temperature channel,
if its THERM limit is exceeded. The PWM output being controlled goes to 100%, if the THERM limit is exceeded and remains at 100%
until the temperature drops below THERM – hysteresis. For acoustic reasons, it is recommended that the hysteresis value not be
programmed less than 4°C. Setting the hysteresis value lower than 4°C causes the fan to switch on and off regularly when the temperature
is close to T
have no effect.
have no effect.
no effect.
0x6F
0x6D
0x6E
0x6A
0x6B
0x6C
[7:0]
MIN
.
Bit Name
Res [7:1]
XEN [0]
HYSL [3:0]
HYSR1 [7:4]
HYSR2 [7:4]
Bit Name
MIN
R/W (Note 1)
R/W (Note 2)
MIN
Hysteresis Registers
R/W
value, the fan remains running at PWM
R/W
R/W
R/W
R/W (Note 1)
(Note 1)
R/W
R/W (Note 2)
R/W
R/W
Allows a twos complement offset value to be automatically
added to or subtracted from the Remote 1 temperature
reading. This is to compensate for any inherent system
offsets such as PCB trace resistance. LSB value = 0.5°C.
Remote 1 THERM limit.
Local THERM limit.
Remote 2 THERM limit.
XNOR tree test enable register.
If the XEN bit is set to 1, the device enters the XNOR tree
test mode. Clearing the bit removes the device from the
XNOR tree test mode.
Unused. Do not write to these bits.
http://onsemi.com
Remote 1 and local temperature hysteresis.
Local temperature hysteresis. 0°C to 15°C of
hysteresis can be applied to the local temperature
AFC and dynamic T
Remote 1 temperature hysteresis. 0°C to 15°C of
hysteresis can be applied to the Remote 1
temperature AFC and dynamic T
Remote 2 temperature hysteresis.
Local temperature hysteresis. 0°C to 15°C of
hysteresis can be applied to the local temperature
AFC and dynamic T
(Note 1)
67
Description
Description
MIN
Description
Description
MIN
MIN
duty cycle until the temperature = T
control loops.
control loops.
MIN
control loops.
0xA4 (100°C)
0xA4 (100°C)
ADT7473: 0xA4 (100°C)
ADT7473−1: 0xC8 (136°C)
Power−On Default
MIN
Power−On Default
Power−On Default
Power−On Default
– hysteresis. Up to
0x44
0x40
0x00
0x00