Power supplies
AN4488
12/50
AN4488 Rev 7
2.3 Analog
Supply
To improve conversion accuracy, the ADC has an independent power supply that can be
filtered separately, and shielded from noise on the PCB.
•
The ADC voltage supply input is available on V
DDA
pin.
•
An isolated supply ground connection is provided on the V
SSA
pin.
In all cases, the VSSA pin should be externally connected to same supply ground than VSS.
To ensure a better accuracy on low-voltage inputs, the user can connect a separate external
reference voltage ADC input on VREF+. The voltage on VREF+ may range from (V
DDA
- 1.2
V) to V
DDA
with a minimum of 1.7 V.
When available (depending on package), V
REF–
must be externally tied to V
SSA
.
