5V
0.22
+
-
1k
1µF
OPA2350
A/B
10µF
JP7/JP8
2.5V from
REF5025
REFIO-A/REFIO-B
0.22
10µF
EVM Analog Interface
2.2
ADSxx54EVM Onboard Reference and ADSxx54 Device Internal Reference
The ADSxx54 dual, simultaneous ADC operates with reference voltages VREF_A and VREF_B present
on pins REFIO_A and REFIO_B, respectively. The ADSxx54 device incorporates two internal individually
programmable 2.5-V reference sources. Alternatively, the onboard 2.5-V reference, REF5025 (U5), can
also be selected. The reference voltage source is determined by setting bit B6 of the ADC configuration
register. Note that this bit is common to ADC_A and ADC_B. Configure the reference settings on the
ADSxx54EVM-PDK by navigating to the
ADSxx54EVM Settings
page on the GUI. Refer to
for
more information. By default, the evaluation module is set up with the onboard external reference source,
with jumpers JP7 and JP8 installed, as shown in
. If the ADSxx54 must be configured with the
internal reference, make sure to remove jumpers JP7 and JP8 before enabling the internal reference.
Figure 3. REF5025 2.5-V External Reference Source and
Reference Driver
6
ADS8354EVM-PDK and ADS7854EVM-PDK
SBAU209 – April 2014
Copyright © 2014, Texas Instruments Incorporated