ST ST10F276E - Page 391

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UM0404 Analog / digital converter
accuracy error introduced by the switched capacitance equivalent resistance is in this
case:
7. So the error due to the voltage partitioning between the real resistive path and C
S
is
less then half a count (considering the worst case when V
A
= 5V):
8. The other conditions to be verified is the time constants of the transients are really and
significantly shorter than the sampling period duration T
S
:
For complete set of parameters characterizing the ST10F276 A/D converter equivalent
circuit, refer to the datasheet.
R
EQ
1
f
C
C
S
---------------10MΩ==
V
A
R
S
R
F
R
L
R
SW
R
AD
+++ +
R
EQ
-------------------------------------------------------------
2.35mV=⋅
1
2
---
LSB
<
τ
1
R
SW
R
AD
+()= C
S
2.8ns=⋅
<<
T
S
= 1μs
10
τ
2
⋅ 10 R⋅
L
= C
S
C
P1
C
P2
++()290ns=⋅
<
T
S
= 1μs