EVM Operation
7
EVM Operation
This section provides information on the analog input, digital control, and general operating conditions of
the ADS833xEVM.
7.1
Analog Input
The four inputs from the ADS8331 (or eight inputs from the ADS8332) are routed directly from the ADC to
header J1 on the EVM board. On the printed circuit board (PCB), there is the option to install a first-order
RC filter on any of the channels. Each channel currently has installed 0
Ω
resistors in series and pads to
install a capacitor (left open by default). Simply replacing the 0
Ω
resistor and installing a capacitor creates
a low-pass filter. Note that each of these analog inputs are referenced to the analog ground of the EVM
board.
The ADS833xEVM also has the option to use an onboard signal conditioning filter between the mux and
ADC input. Using signal conditioning here helps to minimize the cost of a design by allowing the user to
drive all eight of the analog input channels using a single op amp. In the EVM design, the OPA211 is used
in a unity-gain configuration in combination with a 34.8
Ω
and 750pf first-order RC filter. This configuration
has been tested to meet the ac specifications in the
ADS8331 and ADS8332 product data sheet
. See the
appendix for a complete schematic of the EVM board.
7.2
Digital Control
The digital control signals can be applied directly to J6 (top or bottom side). The modular ADS833xEVM
can also be connected directly to a DSP or microcontroller interface board, such as the
or
boards available from Texas Instruments. For a list of compatible interface
and/or accessory boards for the EVM or the ADS8331/32, see the relevant product folder on the TI web
site.
7.3
Default Jumper Settings and Switch Positions
shows the jumpers found on the EVM and the respective factory default conditions for each.
Figure 2. ADS833xEVM Default Jumper Locations
6
ADS833xEVM User
'
s Guide
SBAU176A
–
August 2010
–
Revised May 2011
Copyright
©
2010
–
2011, Texas Instruments Incorporated
