ADT7483AARQZ ON Semiconductor, ADT7483AARQZ Datasheet - Page 10

• Manufacturer Part Number: ADT7483AARQZ
• Description: IC THERM/ALARM 3-CHAN 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADT7483AARQZ

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Full Temp Accuracy: +/- 2.5 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADT7483A
TEMPERATURE MEASUREMENT RESULTS
The results of the local and remote temperature measurements
are stored in the local and remote temperature value registers
and are compared with limits programmed into the local and
remote high and low limit registers.
The local temperature measurement is an 8-bit measurement
with 1°C resolution. The remote temperature measurements are
10-bit measurements, with eight MSBs stored in one register
and two LSBs stored in another register. Table 5 lists the
temperature measurement registers.
Table 5. Register Address for the Temperature Values
Temperature
Channel
Local
Remote 1
Remote 2
By setting Bit 3 of the Configuration 1 Register to 1, the
Remote 2 temperature values can be read from the following
register addresses:
The above is true only when Bit 3 of the Configuration 1
register is set. To read the Remote 1 temperatures, this bit needs
to be switched back to 0.
Only the two MSBs in the remote temperature low byte are
used. This gives the remote temperature measurement a
resolution of 0.25°C. Table 6 shows the data format for the
remote temperature low byte.
Table 6. Extended Temperature Resolution
(Remote Temperature Low Byte)
Extended Resolution
0.00°C
0.25°C
0.50°C
0.75°C
Remote 2, MSBs = 0x01
Remote 2, LSBs = 0x10
MSB Register
Address
0x00
0x01
0x30
Remote Temperature Low Byte
0 000 0000
0 100 0000
1 000 0000
1 100 0000
LSB Register
Address
N/A
0x10 (2 MSBs)
0x33 (2 MSBs)
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When reading the full remote temperature value, both the high
and low byte, the two registers should be read LSB first and then
the MSB. This is because reading the LSB will cause the MSB to
be locked until it is read, guaranteeing that the two values read
are a result of the same temperature measurement.
TEMPERATURE MEASUREMENT RANGE
The temperature measurement range for both local and remote
measurements is, by default, 0°C to 127°C. However, the
ADT7483A can be operated using an extended temperature
range from −64°C to +191°C. This means, the ADT7483A can
measure the full temperature range of a remote thermal diode,
from −55°C to +150°C. The user can switch between these two
temperature ranges by setting or clearing Bit 2 in the Configura-
tion 1 register. A valid result is available in the next measurement
cycle after changing the temperature range.
In extended temperature mode, the upper and lower temperatures
that can be measured by the ADT7483A are limited by the remote
diode selection. The temperature registers themselves can have
values from −64°C to +191°C. However, most temperature sensing
diodes have a maximum temperature range of −55°C to +150°C.
Note that although both local and remote temperature measure-
ments can be made while the part is in extended temperature
mode, the ADT7483A should not be exposed to temperatures
greater than those specified in theAbsolute Maximum Ratings
section. Further, the device is only guaranteed to operate as
specified at ambient temperatures from −40°C to +120°C.
TEMPERATURE DATA FORMAT
The ADT7483A has two temperature data formats. When the
temperature measurement range is from 0°C to 127°C (default),
the temperature data format for both local and remote temperature
results is binary. When the measurement range is in extended
mode, an offset binary data format is used for both local and
remote results. Temperature values in the offset binary data
format are offset by +64. Examples of temperatures in both data
formats are shown in Table 7.