Optional Signal Conditioning Op Amp (U8B)
3-5
EVM Operation
even more capacitance, and by adding a load resistor even improves the
capacitive load drive capability.
Table 3 - 5. Capacitive Load Drive Ouptut Jumper Settings
Jumper Setting
Reference
Unipolar
Bipolar
Function
W3
Open
Open
V
REF
H is disconnected from the inverting input of the output op amp, U2.
W5
2 - 3
1 - 2
Supplies V
SS
power to the negative rail of op amp U2 for bipolar mode,
or ties it to AGND for unipolar mode.
W15
Open
Open
Capacitive load drive output of DAC is routed to pin 1 of W15 jumper, and
may be used as the output terminal.
3.5
Optional Signal Conditioning Op Amp (U8B)
One part of the dual package op amp, OPA2132 (U8), is used for reference
buffering (U8A) while the other is unused. This unused op amp (U8B) is
available for whatever op amp circuit application the user desires to
implement. The 1206 footprint for the resistors and capacitors surrounding the
U8B op amp are not populated, but are available for easy configuration. TP6
and TP7 test points are also not installed, so it is up to the user as to how to
connect the
±
input signals to this op amp. No test point is available for the
output due to space restriction, but a wire can be simply soldered to the output
of the op amp via unused component pads connected to it.
Once the op amp circuit design is realized, configuring the EVM becomes easy
by simply populating the corresponding components that match the circuit
design, and leaving all other unneeded component footprints unpopulated.