ST72F324BJ STMICROELECTRONICS [STMicroelectronics], ST72F324BJ Datasheet - Page 164

• Manufacturer Part Number: ST72F324BJ
• Description: 8-bit MCU, 3.8 to 5.5 V operating range with 8 to 32 Kbyte Flash/ROM, 10-bit ADC, 4 timers, SPI, SCI
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Electrical characteristics
Table 111. 10-bit ADC characteristics (continued)
1. Any added external serial resistor will downgrade the ADC accuracy (especially for resistance greater than 10kΩ). Data
2. Injecting negative current on adjacent pins may result in increased leakage currents. Software filtering of the converted
164/188
Symbol
t
ADC
based on characterization results, not tested in production.
analog value is recommended.
Conversion time (Sample + Hold)
f
f
No. of sample capacitor loading cycles
No. of Hold conversion cycles
CPU
ADC
Figure 84. R
1. C
Figure 85. Recommended C
1. This graph shows that, depending on the input signal variation (f
Figure 86. Typical A/D converter application
= 8 MHz, Speed = 0,
= 2 MHz
the pad capacitance (3pF). A high C
f
stabilization time and decreased to allow the use of a larger serial resistor (R
ADC
PARASITIC
should be reduced.
Parameter
V
AIN
represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus
AIN
R
max. vs f
AIN
C
AIN
ADC
AINx
AIN
45
40
35
30
25
20
15
10
1000
5
0
100
PARASITIC
0.1
with C
10
1
and R
0
0.01
Conditions
AIN
value will downgrade conversion accuracy. To remedy this,
AIN
V
= 0pF
DD
10
0.1
C
values
PARASITIC
V
0.6V
V
0.6V
f
AIN
T
T
(KHz)
(1)
(pF)
30
1
(1)
2kΩ (max)
Cain 10 nF
Cain 22 nF
Cain 47 nF
AIN
I
2 MHz
1 MHz
lkg
), C
70
10
Min
AIN
can be increased for
10-bit A/D
conversion
AIN)
Typ
.
7.5
11
4
ST72XXX
Max
C
12pF
ADC
ST72324B
1/f
Unit
µs
ADC