ADT7463ARQZ ON Semiconductor, ADT7463ARQZ Datasheet - Page 45

• Manufacturer Part Number: ADT7463ARQZ
• Description: IC REMOTE THERMAL CTRLR 24-QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7463ARQZ

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Speed Counter, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 120°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 120°C
• Mounting Type: Surface Mount
• Package / Case: 24-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Register Address
0x64
0x65
0x66
Bit
<7:0>
*These registers become read-only when the ADT7463 is in automatic fan control mode.
Register Address
0x67
0x68
0x69
These are the T
increases with temperature according to T
*These registers become read-only when the Configuration Register 1 Lock bit is set. Any further attempts to write to these registers shall have no effect.
Register Address
0x6A
0x6B
0x6C
If any temperature measured exceeds its THERM limit, all PWM outputs drive their fans at 100% duty cycle. This is a fail-safe mechanism 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.
*These registers become read-only when the Configuration Register 1 Lock bit is set to 1. Any further attempts to write to these registers will have no effect.
Register Address
0x6D
0x6E
Each 4-bit value controls the amount of temperature hysteresis applied to a particular temperature channel. Once the temperature for that channel falls below its
T
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
*These registers become read-only when the Configuration Register 1 Lock bit is set to 1. Any further attempts to write to these registers will have no effect.
REV. C
MIN
value, the fan remains running at PWM
PWM Duty
Cycle
Name
MIN
registers for each temperature channel. When the temperature measured exceeds T
MIN
.
R/W*
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
R/W*
Read/Write
Read/Write
Read/Write
R/W*
Read/Write
Read/Write
Read/Write
R/W*
Read/Write
Read/Write
RANGE
MIN
.
duty cycle until the temperature = T
Table XXVI. Temperature Hysteresis Registers
Table XXIII. PWM Min Duty Cycle Registers
Description
PWM1 Min Duty Cycle
PWM2 Min Duty Cycle
PWM3 Min Duty Cycle
Description
These bits define the PWM
0x00 = 0% duty cycle (Fan off).
0x40 = 25% duty cycle.
0x80 = 50% duty cycle.
0xFF = 100% duty cycle (Fan full speed).
Description
Remote 1 Temp T
Local Temp T
Remote 2 Temp T
Description
Remote 1 THERM Limit
Local THERM Limit
Remote 2 THERM Limit
Description
Remote 1 Local Temp Hysteresis
Remote 2 Temp Hysteresis
Table XXV. THERM Limit Registers
Rev. 4 | Page 45 of 52 | www.onsemi.com
Table XXIV. T
MIN
MIN
MIN
–45–
MIN
MIN
Registers
– Hysteresis. Up to 15°C of hysteresis may be assigned to any temperature
MIN
duty cycle for PWMx.
MIN
, the appropriate fan runs at minimum speed and
Power-On Default
0x80 (50% duty cycle)
0x80 (50% duty cycle)
0x80 (50% duty cycle)
Power-On Default
0x5A (90�C)
0x5A (90�C)
0x5A (90�C)
Power-On Default
0x64 (100�C)
0x64 (100�C)
0x64 (100�C)
Power-On Default
0x44
0x40
ADT7463