ADT7475ARQZ ON Semiconductor, ADT7475ARQZ Datasheet - Page 9

• Manufacturer Part Number: ADT7475ARQZ
• Description: IC REMOTE THERMAL CTRLR 16-QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7475ARQZ

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Speed Counter, 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 ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Full Temp Accuracy: +/- 0.5 C
• Digital Output - Bus Interface: Serial (3-Wire, 4-Wire)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

the tenth clock pulse, and then high during the tenth clock
pulse to assert a stop condition.
serial bus in one operation, but it is not possible to mix read
and write in one operation because the type of operation is
determined at the beginning and cannot subsequently be
changed without starting a new operation.
two bytes, and read operations contain one byte. To write
data to one of the device data registers or read data from it,
the address pointer register must be set so that the correct
data register is addressed, and then data can be written to that
register or read from it. The first byte of a write operation
always contains an address that is stored in the address
pointer register. If data is to be written to the device, the write
operation contains a second data byte that is written to the
register selected by the address pointer register.
address is sent over the bus, and then R/W is set to 0. This
is followed by two data bytes. The first data byte is the
Figure 13. Writing a Register Address to the Address Pointer Register, then Writing Data to the Selected Register
Any number of bytes of data can be transferred over the
In the ADT7475, write operations contain either one or
This write operation is shown in Figure 13. The device
SDA
SCL
SCL
SDA
START BY
MASTER
START BY
MASTER
SDA
SCL
START BY
MASTER
1
0
1
0
1
0
1
1
Figure 15. Reading Data from a Previously Selected Register
SERIAL BUS ADDRESS BYTE
1
SERIAL BUS ADDRESS BYTE
Figure 14. Writing to the Address Pointer Register Only
0
0
SERIAL BUS ADDRESS BYTE
0
1
FRAME 1
1
FRAME 1
1
FRAME 1
1
1
SDA (CONTINUED)
1
SCL (CONTINUED)
1
1
1
http://onsemi.com
0
0
0
R/W
R/W
ADT7475
ACK. BY
ADT7475
ACK. BY
R/W
9
9
ADT7475
ACK. BY
9
address of the internal data register to write to, which is
stored in the address pointer register. The second data byte
is the data to write to the internal data register.
possibilities:
•
•
D7
When reading data from a register, there are two
If the ADT7475 address pointer register value is
unknown or not the desired value, it must first be set to
the correct value before data can be read from the
desired data register. This is done by performing a write
to the ADT7475 as before, but only the data byte
containing the register address is sent, because no data
is written to the register see Figure 14.
A read operation is then performed consisting of the
serial bus address; the R/W bit set to 1, followed by the
data byte read from the data register see Figure 15.
If the address pointer register is known to be already at
the desired address, data can be read from the
corresponding data register without first writing to the
address pointer register see Figure 15.
9
1
D7
1
D7
1
D7
D6
1
D6
D6
ADDRESS POINTER REGISTER BYTE
D6
D5
D5
D5
ADDRESS POINTER REGISTER BYTE
DATA BYTE FROM ADT745
D5
D4
D4
D4
DATA BYTE
FRAME 3
FRAME 2
D4
D3
FRAME 2
D3
D3
FRAME 2
D3
D2
D2
D2
D2
D1
D1
D1
D1
D0
D0
D0
ADT7475
ACK. BY
NO ACK. BY
MASTER
ADT7475
ACK. BY
D0
9
9
9
ADT7475
ACK. BY
STOP BY
MASTER
9
STOP BY
MASTER
STOP BY
MASTER