Specifications
Sensors
Current, light, and proximity sensing
www.digikey.com/maxim-industrial 77
Benefits
• Monitor current directly at the supply
side for highly accurate sensing
– The MAX9922 allows direct interface to
28V signals
– The MAX9922/MAX9923 use a patented
spread-spectrum autozeroing technique*
to remove offset and eliminate drift over
time and temperature
– 12-bit ADCs
• Versatile and simple solutions
accommodate a range of performance
and cost-based requirements
– Pin-compatible 8-, 10-, and 12-bit ADCs in
the same package
– 4 to 12 ADC channels on a 2-wire I
2
C bus
MAX9922/MAX9923, MAX11601, MAX11607,
MAX11613 families
Here is a very common circuit found in applications for power
monitoring. The MAX9923 current-sense amplifier amplifies the
differential voltage across the current-sense resistor with extremely
low offset and low noise.
The output of the MAX9923 and a resistor-divided output of the
supply is fed to a low-cost, 4-channel 12-bit ADC, the MAX11613.
While two independent supplies are shown here, the ADC could
be monitoring voltage and current on a group of supplies. The
MAX11601, MAX11607, MAX11613 families of ADCs are ideal for this
application as they provide a low-cost, small package (µMAX® or
QSOP) I
2
C solution with 4 to 12 channels.
*U.S. Patent #6,847,257.
Improve efficiency and increase reliability by monitoring a system’s power
Circuit for monitoring a system’s power supplies.
MAX9923T
MAX9923H
MAX9923F
GND
OUT
RS+ RS-
RSB
*OPTIONAL NOISE REDUCTION
FB
V
DD
3.3V
SHDN
ON
OFF
1nF*
REF
V
SENSE
R
LOAD
BATT
1.9V TO
28V
MAX9923T
MAX9923H
MAX9923F
GND
OUT
RS+ RS-
RSB
FB
V
DD
3.3V
SHDN
ON
OFF
1nF*
REF
V
SENSE
R
LOAD
BATT
1.9V TO
28V
MAX11613