ST7-STICK45 STMICROELECTRONICS [STMicroelectronics], ST7-STICK45 Datasheet - Page 105

• Manufacturer Part Number: ST7-STICK45
• Description: 8-bit microcontroller with single voltage Flash memory, data EEPROM, ADC, timers, SPI
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ADC CHARACTERISTICS (Cont’d)
Figure 82. R
Notes:
1. C
pacitance (3pF). A high C
2. This graph shows that depending on the input signal variation (f
the use of a larger serial resistor (R
13.11.1 General PCB Design Guidelines
To obtain best results, some general design and
layout rules should be followed when designing
the application PCB to shield the noise-sensitive,
analog physical interface from noise-generating
CMOS logic signals.
Properly place components and route the signal
traces on the PCB to shield the analog inputs. An-
45
40
35
30
25
20
15
10
PARASITIC
5
0
0
represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the pad ca-
AIN
max. vs f
10
C
PARASITIC
PARASITIC
(pF)
ADC
30
AIN)
with C
value will downgrade conversion accuracy. To remedy this, f
4 MHz
2 MHz
1 MHz
. It is valid for all f
70
AIN
=0pF
1)
ADC
frequencies ≤ 4MHz.
Figure 83. Recommended C
alog signals paths should run over the analog
ground plane and be as short as possible. Isolate
analog signals from digital signals that may switch
while the analog inputs are being sampled by the
A/D converter. Do not toggle digital outputs on the
same I/O port as the A/D input being converted.
AIN
1000
100
0.1
10
), C
1
AIN
0.01
can be increased for stabilization and to allow
ST7LITE0xY0, ST7LITESxY0
0.1
f
AIN
(KHz)
1
ADC
AIN
Cain 10 nF
Cain 22 nF
Cain 47 nF
/R
should be reduced.
AIN
10
values
105/124
2)