Rainbow Electronics MAX6683 - Manual (Page 13)

upper byte contains the MSBs, while the lower byte
contains the 3LSBs (Figure 5). D9–D3 of the upper byte
represent the whole decimal number of the temperature
conversion and D10 is sign. D2–D0 of the lower byte
represent 1/2, 1/4, 1/8 of a degree, respectively, and
the remaining bits are disregarded.
Nine-bit temperature data (8 bits plus sign) is obtained
by setting bit 5 of the Configuration Register (address
40h) to 1, reducing the conversion time by a factor of
four, and executing a Read Word command to the
Temperature Data Register (address 27h). The upper
byte contains the MSBs, while the lower byte contains
the LSB (Figure 5). D7–D1 of the upper byte represent
the whole decimal number of the temperature conver-
sion and D0 is sign. D0 of the lower byte represents 1/2
of a degree, and the remaining bits are disregarded.
Applications Information
Sensing Circuit Board and
Component Temperatures
Temperature sensor ICs like the MAX6683 that sense
their own die temperatures must be mounted on or
close to the object whose temperature they are intend-
ed to measure. Because there is a good thermal path
between the 10-pin µMAX package’s metal leads and
the IC die, the MAX6683 can accurately measure the
temperature of the circuit board to which it is soldered.
If the sensor is intended to measure the temperature of
a heat-generating component on the circuit board, it
should be mounted as close as possible to that compo-
nent and should share supply and ground traces (if
they are not noisy) with that component where possible.
This maximizes the heat transfer from the component to
the sensor.
The thermal path between the plastic package and the
die is not as good as the path through the leads, so the
MAX6683, like all temperature sensors in plastic pack-
ages, is less sensitive to the temperature of the sur-
rounding air than to the temperature of the leads.
Wiring and circuits must be kept insulated and dry to
avoid leakage and corrosion, especially if they operate
at cold temperatures where condensation can occur.
Chip Information
TRANSISTOR COUNT: 13,446
PROCESS: BiCMOS
MAX6683
Temperature Sensor and System Monitor
in a 10-Pin µMAX
______________________________________________________________________________________ 13
V CC
SCL
SDA
ADD
5.0V
IN
1.8V IN
2.5V IN
ALERT
ADC
VOLTAGE
REFERENCE
DATA AND
CONTROL
LOGIC
TEMPERATURE
SENSOR
INPUT VOLTAGE
SCALING AND
MULTIPLEXER
I 2 C/SMBus-
COMPATIBLE
INTERFACE
Functional Diagram