Datasheet

Applications Information
Digital Noise
The MAX7500–MAX7504 feature an integrated lowpass
filter on both the SCL and the SDA digital lines to miti-
gate the effects of bus noise. Although this filtering
makes communication robust in noisy environments,
good layout practices are always recommended.
Minimize noise coupling by keeping digital traces away
from switching power supplies. Ensure that digital lines
containing high-speed data communications cross at
right angles to the SDA and SCL lines.
Excessive noise coupling into the SDA and SCL lines
on the MAX7500–MAX7504—specifically noise with
amplitude greater than 400mV
P-P
(the MAX7500–
MAX7504s’ typical hysteresis), overshoot greater than
300mV above +V
S
, and undershoot more than 300mV
below GND—may prevent successful serial communi-
cation. Serial bus no-acknowledge is the most common
symptom, causing unnecessary traffic on the bus.
Care must be taken to ensure proper termination within
a system with long PCB traces or multiple parts on the
bus. Resistance can be added in series with the SDA
and SCL lines to further help filter noise and ringing. If it
proves to be necessary, a 5kΩ resistor should be
placed in series with the SCL line, placed as close as
possible to SCL. This 5kΩ resistor, with the 5pF to 10pF
stray capacitance of the MAX7500–MAX7504 provide a
6MHz to 12MHz lowpass filter, which is sufficient filter-
ing in most cases.
Chip Information
PROCESS: CMOS
MAX7500–MAX7504
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
______________________________________________________________________________________ 11
Ordering Information/
Selector Guide (continued)
PART
TEMP
RANGE
PIN-
PACKAGE
RESET TIMEOUT
MAX7500MSA+
-55°C to
+125°C
8 SO X X
MAX7500MUA
-55°C to
+125°C
8 µMAX X X
MAX7500MUA+
-55°C to
+125°C
8 µMAX X X
MAX7501MSA
-55°C to
+125°C
8 SO X X
MAX7501MSA+
-55°C to
+125°C
8 SO X X
MAX7501MUA
-55°C to
+125°C
8 µMAX X X
MAX7501MUA+
-55°C to
+125°C
8 µMAX X X
MAX7502MSA
-55°C to
+125°C
8 SO X —
MAX7502MSA+
-55°C to
+125°C
8 SO X —
MAX7502MUA
-55°C to
+125°C
8 µMAX X —
MAX7502MUA+
-55°C to
+125°C
8 µMAX X —
MAX7503MSA
-55°C to
+125°C
8 SO X —
MAX7503MSA+
-55°C to
+125°C
8 SO X —
MAX7503MUA
-55°C to
+125°C
8 µMAX X —
MAX7503MUA+
-55°C to
+125°C
8 µMAX X —
MAX7504MSA
-55°C to
+125°C
8 SO X —
MAX7504MSA+
-55°C to
+125°C
8 SO X —
MAX7504MUA
-55°C to
+125°C
8 µMAX X —
MAX7504MUA+
-55°C to
+125°C
8 µMAX X —
+ Denotes a lead(Pb)-free/RoHS-compliant package.
1
2
3
4
8
7
6
5
+V
S
A0
A1
A2GND
OS
SCL
SDA
MAX7500
μMAX, SO
1
2
3
4
8
7
6
5
+V
S
A0
A1
RESETGND
OS
SCL
SDA
MAX7501–
MAX7504
μMAX, SO
TOP VIEW
Pin Configurations