REF5045
4.5 V
OPA333
+
-
THS4281
REF
1 F
1 k
+
±
1 F
20 k
1 k
1 F
5 V
0.22
10 F
5 V
EVM Analog Interface
2.3
Voltage Reference
Because the EVM is powered by a 5-V analog supply, make sure to use a value below 5 V for the
reference. This EVM uses a 4.5-V reference, created by the onboard
, as shown in
. The
REF5045 output is filtered by an RC filter with a 160-Hz cutoff frequency to minimize noise contribution.
The EVM is buffered by the
, which drives the 10
μ
F capacitor required at the ADC reference
input. The
with additional feedback is optional, but does complement the THS4281, and
minimizes offset and drift.
Figure 3. THS4281 Reference Driver with Complementary OPA333 for Drift and Offset Correction
5
SBAU233A – October 2014 – Revised November 2015
ADS8339EVM-PDK
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