ADM1023ARQZ ON Semiconductor, ADM1023ARQZ Datasheet - Page 13

• Manufacturer Part Number: ADM1023ARQZ
• Description: IC SENSOR TEMP DUAL PREC 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADM1023ARQZ

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: 0°C ~ 120°C, External Sensor
• Output Type: SMBus™
• Output Alarm: Yes
• Output Fan: No
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: 0°C ~ 120°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Full Temp Accuracy: +/- 1 C, +/- 3 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Maximum Operating Temperature: + 120 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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, while read operations contain one byte and
perform the following functions:
data from it, the address pointer register must be set so that
the correct data register is addressed. Data can then be
written into that register or read from it. The first byte of a
write operation always contains a valid 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.
over the bus followed by R/W set to 0. This is followed by
two data bytes. The first data byte is the address of the
internal data register to be written to, which is stored in the
address pointer register. The second data byte is the data to
be written to the internal data register.
possibilities:
NOTES:
•
Any number of bytes of data may be transferred over the
For the ADM1023, write operations contain either one or
To write data to one of the device data registers or read
This is illustrated in Figure 15. The device address is sent
When reading data from a register, there are two
It is possible to read a data byte from a data register
without first writing to the address pointer register.
However, it is not possible to write data to a register
without writing to the address pointer register even if
1. If the ADM1023’s address pointer register value is
2. If the address pointer register is known to be at the
unknown or not the desired value, it is necessary
to set it to the correct value before data can be read
from the desired data register. This is done by
performing a write to the ADM1023 as before, but
only the data byte containing the register read
address is sent, as data is not to be written to the
register. This is shown in Figure 16.
A read operation is then performed consisting of
the serial bus address, R/W bit set to 1, followed
by the data byte read from the data register. This is
shown in Figure 17.
desired address already, data can be read from the
corresponding data register without first writing to
the address pointer register.
SDATA
SCLK
START BY
MASTER
A6
1
Figure 17. Reading Data from a Previously Selected Register
A5
SERIAL BUS ADDRESS BYTE
A4
A3
FRAME 1
A2
A1
http://onsemi.com
A0
ADM1023
R/W
13
ADM1023
ACK. BY
•
ALERT Output
measurement is detected or if the remote temperature sensor
is open−circuit. It is an open drain and requires a 10 kW
pull−up to V
wire−AND’ed together, so that the common line goes low if
one or more of the ALERT outputs goes low.
processor, or it may be used as an SMBALERT. Slave
devices on the SMBus normally cannot signal to the master
that they want to talk, but the SMBALERT function allows
them to do so.
SMBALERT line connected to the master. When the
SMBALERT line is pulled low by one of the devices, the
procedure shown in Figure 18 occurs.
SMBALERT Process
9
The ALERT output goes low whenever an out−of−limit
The ALERT output can be used as an interrupt signal to a
One or more ALERT outputs are connected to a common
the address pointer register is already at the correct
value. This is because the first data byte of a write is
always written to the address pointer register.
Do not forget that ADM1023 registers have different
addresses for read and write operations. The write
address of a register must be written to the address
pointer if data is to be written to that register, but it is
not possible to read data from that address. The read
address of a register must be written to the address
pointer before data can be read from that register.
1. SMBALERT pulled low.
2. Master initiates a read operation and sends the
3. The device whose ALERT output is low responds
MASTER
RECEIVES
SMBALERT
START
D7
1
alert response address (ARA = 0001 100). This is
a general call address that must not be used as a
specific device address.
to the ARA and the master reads its device
address. The address of the device is now known,
and it can be interrogated in the usual way.
D6
ALERT RESPONSE
Figure 18. Use of SMBALERT
MASTER SENDS
ARA AND READ
DD
D5
ADDRESS
COMMAND
DATA BYTE FROM ADM1023
. Several ALERT outputs can be
D4
FRAME 2
D3
RD ACK
D2
DEVICE SENDS
ITS ADDRESS
D1
ADDRESS
DEVICE
D0
BY MASTER
NO ACK.
ACK
NO
9
STOP
STOP BY
MASTER