ADT7462ACPZ-REEL ON Semiconductor, ADT7462ACPZ-REEL Datasheet - Page 20

• Manufacturer Part Number: ADT7462ACPZ-REEL
• Description: IC TEMP/VOLT MONITOR 32-LFCSP
• Manufacturer: ON Semiconductor

Specifications of ADT7462ACPZ-REEL

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 32-LFCSP
• Number Of Voltages Monitored: 1
• Monitored Voltage: 0.9 V to 12 V
• Manual Reset: Not Resettable
• Watchdog: No Watchdog
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 3 V
• Supply Current (typ): 4000 uA
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

be read first and then the MSB. Reading the LSBs causes the
current MSBs to be frozen until they are read. Reading the
MSBs only does not cause any register to be locked. This is
useful when a temperature reading with 1°C resolution is
required.
Series Resistance Cancellation
D− inputs can be caused by a variety of factors, including
PCB track resistance and track length. This series resistance
appears as a temperature offset in the remote sensor’s
temperature measurement. This error typically causes a
0.8°C offset per ohm of parasitic resistance in series with the
remote diode.
series resistance on the temperature reading, giving a more
accurate result, without the need for user characterization of
this resistance. The ADT7462 is designed to automatically
cancel typically up to 2 kW of resistance. By using an
advanced temperature measurement method, the process is
transparent to the user. This feature also allows an RCR filter
to be added to the sensor path, allowing the part to be used
accurately in noisy environments.
Temperature Limits
low temperature limit associated with it. The temperature
measurements are compared with these limits, and the
results of these comparisons are stored in status registers. A
Logic 0 indicates an in−limit comparison, and a Logic 1
indicates an out−of−limit comparison. The ADT7462 can
generate an ALERT, if configured to do so, after a status bit
is set. For more information on the status registers and
ALERT, see the Status and Mask Registers ALERT section.
THERM2 temperature limit associated with it. When these
temperature limits are exceeded, the corresponding
THERM pin is asserted low (if THERM is configured as an
output), and the fans are boosted to full speed (if the boost
bit is set). Table 10 shows a complete list of all the
temperature limits and their default values.
When reading the full temperature value, the LSB should
Parasitic resistance in series with the remote diode D+ and
The ADT7462 automatically cancels out the effect of this
Each temperature measurement channel has a high and
Each temperature channel also has a THERM1 and a
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20
Offset Registers
0x56 to Register 0x59 for the local, Remote 1, Remote 2, and
Remote 3 temperature channels. By doing a one−time
calibration of the system, the user can determine the offset
caused by system board noise and cancel it using the offset
registers. The offset registers automatically add a twos
complement,
measurement. The LSBs add 0.5°C offset to the temperature
reading so the 8−bit register effectively allows temperature
offsets of up to ±64°C with a resolution of 0.5°C. This ensures
that the readings in the temperature measurement registers are
as accurate as possible.
Temperature Offset Registers
Register 0x56 Local Temperature Offset = 0x00 (00°C default)
Register 0x57 Remote 1 Temperature Offset = 0x00
(0°C default)
Register 0x58 Remote 2 Temperature Offset = 0x00
(0°C default)
Register 0x59 Remote 3 Temperature Offset = 0x00
(0°C default)
Table 10. Temperature Limit Registers
Local Low Temperature Limit
Remote 1 Low Temperature Limit
Remote 2 Low Temperature Limit
Remote 3 Low Temperature Limit
Local High Temperature Limit
Remote 1 High Temperature Limit
Remote 2 High Temperature Limit
Remote 3 High Temperature Limit
Local THERM1 Temperature Limit
Remote 1 THERM1 Temperature Limit
Remote 2 THERM1 Temperature Limit
Remote 3 THERM1 Temperature Limit
Local THERM2 Temperature Limit
Remote 1 THERM2 Temperature Limit
Remote 2 THERM2 Temperature Limit
Remote 3 THERM2 Temperature Limit
The ADT7462 has temperature offset registers at Register
Temperature Value
8−bit
reading
to
every
Register
Address
0x4A
0x4B
0x4C
0x4D
0x4E
0x4F
0x44
0x45
0x46
0x47
0x48
0x49
0x50
0x51
0x52
0x53
temperature
Default
0xA4
0xA4
0xA4
0xA4
0xA4
0xA4
0xA4
0xA4
0x40
0x40
0x40
0x40
0x95
0x95
0x95
0x95