MAX126 Maxim, MAX126 Datasheet - Page 13

• Manufacturer Part Number: MAX126
• Description: (MAX125 / MAX126) 2x4-Channel / Simultaneous-Sampling 14-Bit DAS
• Manufacturer: Maxim

brought to the MAX125/MAX126 at CH4B. The addi-
tional channels can be used to evaluate slower analog
inputs, such as the main DC bus voltage (CH2B), tem-
perature sensors (CH3B), or other analog inputs (AUX,
CH1B).
For optimum system performance, use printed circuit
boards with separate analog and digital ground
planes. Wire-wrapped boards are not recommended.
Connect the two ground planes together at the low-
impedance power-supply source. Connect DGND and
AGND together at the IC. For the best ground connec-
tion, connect the DGND and AGND pins together and
Figure 10. Vector Motor Control
SETPOINTS
EXTERNAL
CONTROLLER
DSP
______________________________________________________________________________________
C
and Ground Management
Power-Supply Bypassing
2x4-Channel, Simultaneous-Sampling
14
POWER
14 BIT ADC +
STAGE
SEQUENCER
MAX125
MAX126
MICRO-
MAIN DC
CH1
CH2
CH3
CH4
A
B
A
B
A
B
A
B
connect that point to the system analog ground plane
to avoid interference from other digital noise sources. If
DGND is connected to the system digital ground, digi-
tal noise may get through to the ADC’s analog portion.
The AGND pins must be connected directly to a low-
impedance ground plane. Extra impedance between
the pins and the ground plane increases crosstalk and
degrades INL.
Bypass AV
to AGND. Mount them with short leads close to the
device. Ferrite beads may also be used to further iso-
late the analog and digital power supplies. Bypass
DV
MAIN DC
AUX
TEMP
DD
with a 0.1µF ceramic capacitor to DGND.
DD
and AV
SS
with 0.1µF ceramic capacitors
FEEDBACK
VELOCITY
14-Bit DAS
MOTOR
MOTOR
AC
AC
RESOLVER/
ENCODER
R/E
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