Datasheet

ADS7834
13
SBAS098A
www.ti.com
With this in mind, power to the ADS7834 should be clean
and well bypassed. A 0.1µF ceramic bypass capacitor should
be placed as close to the device as possible. In addition, a
1µF to 10µF capacitor is recommended. If needed, an even
larger capacitor and a 5Ω or 10Ω series resistor my be used
to lowpass filter a noisy supply.
The ADS7834 draws very little current from an external
reference on average as the reference voltage is internally
buffered. However, glitches from the conversion process
appear at the V
REF
input and the reference source must be
able to handle this. Whether the reference is internal or
external, the V
REF
pin should be bypassed with a 0.1µF
capacitor. An additional larger capacitor may also be used,
if desired. If the reference voltage is external and originates
from an op-amp, make sure that it can drive the bypass
capacitor or capacitors without oscillation.
The GND pin should be connected to a clean ground point.
In many cases, this will be the “analog” ground. Avoid
connections which are too near the grounding point of a
microcontroller or digital signal processor. If needed, run a
ground trace directly from the converter to the power supply
entry point. The ideal layout will include an analog ground
plane dedicated to the converter and associated analog
circuitry.