Datasheet

SMBus Digital Interface
From a software perspective, the MAX6698 appears as
a series of 8-bit registers that contain temperature mea-
surement data, alarm threshold values, and control bits.
A standard SMBus-compatible 2-wire serial interface is
used to read temperature data and write control bits
and alarm threshold data. The same SMBus slave
address also provides access to all functions.
The MAX6698 employs four standard SMBus protocols:
write byte, read byte, send byte, and receive byte
(Figure 2). The shorter receive byte protocol allows
quicker transfers, provided that the correct data regis-
ter was previously selected by a read byte instruction.
Use caution with the shorter protocols in multimaster
systems, since a second master could overwrite the
command byte without informing the first master. Figure
3 is the SMBus write timing diagram and Figure 4 is the
SMBus read timing diagram.
The remote diode 1 measurement channel provides 11
bits of data (1 LSB = 0.125°C). All other temperature-
measurement channels provide 8 bits of temperature
data (1 LSB = 1°C). The 8 most significant bits (MSBs)
can be read from the local temperature, remote tem-
perature, and thermistor registers. The remaining 3 bits
MAX6698
_______________________________________________________________________________________ 7
DXP1
DXN1
3-TO-1
MUX
INPUT
BUFFER
ADC
10/100µA
V
CC
CNT
COUNTER
VREF
COMMAND BYTE
REMOTE TEMPERATURES
LOCAL TEMPERATURES
REGISTER BANK
ALERT THRESHOLD
OVERT THRESHOLD
ALERT RESPONSE ADDRESS
ALU
DP
VREF1
SMBus
INTERFACE
MAX6698
SCL SDA
OVERT
ALERT
DXP3
DXN3
BUF1
BUF2
3-TO-1
MUX
R
EXT1
R
THER1
R
EXT2
R
THER1
R
EXT1
R
THER1
Figure 1. Internal Block Diagram
7-Channel Precision Remote-Diode, Thermistor,
and Local Temperature Monitor