LTC1856_15 Datasheet, PDF (22/24 Pages) Linear Technology – 8-Channel, 10V Input 12-/14-/16-Bit, 100ksps ADC Converters with Shutdown

LTC1854/LTC1855/LTC1856
applications information
LTC1855/LTC1856 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 ADC through a wide, low inductance path.
LTC1854/
LTC1855/
CH0 LTC1856
CH1
CH2
MUXOUT^{+ 10 12} _ADC⁺
CH3
LTC1854/LTC1855/LTC1856
+–
CH4
CH5
MUXOUT^– _{11 13} ADC^– _VREF
REFCOMP AGND
AV_DD
DV_DD DGND OV_DD
DIGITAL
SYSTEM
CH6
15
16
14, 17, 18 19
20
24
21
CH7
COM
1µF
10µF
10µF
10µF
10µF
ANALOG GROUND PLANE
DIGITAL
GROUND PLANE
18545 F13
Figure 13. Power Supply Grounding Practice
22
185456fa