MAX6698UE38+ Maxim Integrated Products, MAX6698UE38+ Datasheet - Page 8

• Manufacturer Part Number: MAX6698UE38+
• Description: IC TEMP MONITOR 7CH 16-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6698UE38+

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Buffer, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Full Temp Accuracy: +/- 3.5 C, +/- 3 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 11 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

for remote diode 1 can be read from the extended tem-
perature register. If extended resolution is desired, the
extended resolution register should be read first. This
prevents the most significant bits from being overwritten
by new conversion results until they have been read. If
the most significant bits have not been read within an
SMBus timeout period (nominally 25ms), normal updat-
ing continues. Table 1 shows themistor voltage data for-
mat. Table 2 shows the main temperature register (high
byte) data format. Table 3 shows the extended resolu-
tion temperature register (low byte) data format.
If a channel’s input DXP_ and DXN_ are left open, the
MAX6698 detects a diode fault. An open diode fault
does not cause either ALERT or OVERT to assert. A bit
in the status register for the corresponding channel is
set to 1 and the temperature data for the channel is
stored as all 1s (FFh). It takes approximately 4ms for
the MAX6698 to detect a diode fault. Once a diode fault
is detected, the MAX6698 goes to the next channel in
the conversion sequence. Depending on operating
conditions, a shorted diode may or may not cause
ALERT or OVERT to assert, so if a channel will not be
used, disconnect its DXP and DXN inputs.
7-Channel Precision Remote-Diode, Thermistor,
and Local Temperature Monitor
Figure 2. SMBus Protocols
8
Write Byte Format
Read Byte Format
Send Byte Format
S = Start condition
P = Stop condition
S
S
_______________________________________________________________________________________
S
ADDRESS
Slave Address: equiva-
lent to chip-select line
ADDRESS
7 bits
Slave Address: equiva-
lent to chip-select line of
a 3-wire interface
7 bits
ADDRESS
7 bits
WR
WR
Shaded = Slave transmission
/// = Not acknowledged
ACK
Diode Fault Detection
ACK
WR
Command Byte: sends com-
mand with no data, usually
used for one-shot command
COMMAND
8 bits
Command Byte: selects
which register you are
reading from
COMMAND
ACK
8 bits
ACK
Command Byte: selects which
register you are writing to
ACK
COMMAND
P
8 bits
S
Receive Byte Format
There are 11 alarm threshold registers that store over-
temperature ALERT and OVERT threshold values.
Seven of these registers are dedicated to store one
local alert temperature threshold limit, three remote alert
temperature threshold limits, and three thermistor volt-
age threshold limits (see the
tion). The remaining four registers are dedicated to
remote-diode channel 1, and three thermistor channels
1, 2, and 3 to store overtemperature threshold limits
(see the OVERT Overtemperature Alarm section).
Access to these registers is provided through the
SMBus interface.
Table 1. Thermistor Voltage Data Format
S
Slave Address: repeated
due to change in data-
flow direction
ADDRESS
7 bits
ADDRESS
ACK
7 bits
V
1.000
0.500
0.250
0.055
0.050
0.005
0.000
REXT
Data Byte: data goes into the register
set by the command byte (to set
thresholds, configuration masks, and
sampling rate)
RD
DATA
RD
8 bits
Alarm Threshold Registers
ACK
ACK
ALERT Interrupt Mode sec-
Data Byte: reads data from
the register commanded
by the last read byte or
write byte transmission;
also used for SMBus alert
response return address
Data Byte: reads from
the register set by the
command byte
DATA
8 bits
DATA
8 bits
DIGITAL OUTPUT
ACK
1100 1000
0110 0100
0011 0010
0000 1011
0000 1010
0000 0001
0000 0000
///
///
P
1
P
P