MC68HC16Z1CPV16 Datasheet, PDF (202/500 Pages) Freescale Semiconductor, Inc – Symbols and Operators, CPU16 Register Mnemonics

Freescale Semiconductor, Inc.
3FF
3FE
3FD
3FC
3FB
3FA
8
7
6
5
4
3
2
1
0
.010 .020 .030 5.100 5.110 5.120 5.130
INPUT IN VOLTS (V_RH = 5.120 V, V_RL = 0 V)
Figure 8-5 Errors Resulting from Clipping
ADC CLIPPING
8.8.3 Analog Supply Filtering and Grounding
Two important factors influencing performance in analog integrated circuits are supply
filtering and grounding. Generally, digital circuits use bypass capacitors on every V_DD/
V_SS pin pair. This applies to analog subsystems or submodules also. Equally important
as bypassing is the distribution of power and ground.
Analog supplies should be isolated from digital supplies as much as possible. This ne-
cessity stems from the higher performance requirements often associated with analog
circuits. Therefore, deriving an analog supply from a local digital supply is not recom-
mended. However, if for economic reasons digital and analog power are derived from
a common regulator, filtering of the analog power is recommended in addition to the
bypassing of the supplies already mentioned. For example, an RC low-pass filter could
be used to isolate the digital and analog supplies when generated by a common reg-
ulator. If multiple high precision analog circuits are locally employed (such as two A/D
converters), the analog supplies should be isolated from each other, as sharing sup-
plies introduces the potential for interference between analog circuits.
8-16
ANALOG-TO-DIGITAL CONVERTER
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M68HC16 Z SERIES
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