SPC5604BF2MLL6 Datasheet, PDF (71/109 Pages) Freescale Semiconductor, Inc – MPC5604B/C Microcontroller

3.26 ADC electrical characteristics
Package pinouts and signal descriptions
3.26.1 Introduction
The device provides a 10-bit Successive Approximation Register (SAR) analog-to-digital converter.
1023
1022
1021
1020
1019
1018
Offset error (E_O)
Gain error (E_G)
1 LSB ideal = V_{DD_ADC} / 1024
(2)
code out
7
(1)
6
5
(5)
(1) Example of an actual transfer curve
4
(2) The ideal transfer curve
(3) Differential non-linearity error (DNL)
3
(4)
(4) Integral non-linearity error (INL)
(5) Center of a step of the actual transfer curve
2
(3)
1
1 LSB (ideal)
0
1 23 45 67
Offset error (E_O)
1017 1018 1019 1020 1021 1022 1023
V_in(A) (LSB_ideal)
Figure 19. ADC characteristic and error definitions
3.26.2 Input impedance and ADC accuracy
In the following analysis, the input circuit corresponding to the precise channels is considered.
To preserve the accuracy of the A/D converter, it is necessary that analog input pins have low AC impedance. Placing a capacitor
with good high frequency characteristics at the input pin of the device can be effective: the capacitor should be as large as
MPC5604B/C Microcontroller Data Sheet, Rev. 11
Freescale Semiconductor
71