LTC1857/LTC1858/LTC1859
19
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For more information www.linear.com/LTC1857
APPLICATIONS INFORMATION
1859 F13
ADC
+
LTC1857/LTC1858/LTC1859
DIGITAL
SYSTEM
OV
DD
DGND
24 21
ADC
–
10µF
DV
DD
20
10µF
AV
DD
19
AGND
14, 17, 18
10µF
REFCOMP
16
10µF
V
REF
15
12
MUXOUT
+
LTC1857/
LTC1858/
LTC1859
MUXOUT
–
10
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
11
13
1µF
ANALOG GROUND PLANE
+
–
Figure 13. Power Supply Grounding Practice
LTC1858/LTC1859
can be tied to the analog ground plane.
Placing the bypass capacitor as close as possible to the
power supply pins, the reference and reference buffer out
-
put is very important. Low impedance common returns for
these bypass capacitors are essential to low noise operation
of the ADC, and the foil width for these tracks should be
as wide as possible. Also, since any potential difference in
grounds between the signal source and ADC appears as
an error voltage in series with the input signal, attention
should be paid to reducing the ground circuit impedance
as much as possible. The digital output latches and the
onboard sampling clock have been placed on the digital
ground plane. The two ground planes are tied together at
the power supply ground connection.
