C517A_99 Datasheet, PDF (169/218 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C517A
Note : The prescaler ratios in table 6-14 are mimimum values. At system clock rates (f_OSC) up to
16 MHz the divider ratio 4 and 8 can be used. At system clock rates greater than 16 MHz only
the divider ratio 8 can be used. Using higher divider ratios than required increases the total
conversion time but can be useful in applications which have voltage sources with higher
input resistances for the analog inputs (increased sample phase).
30
µs
t_ADCC
20
t_{ADCC min} = 6 µs
MCD03316
10
6
Prescaler ÷ 4
Prescaler ÷ 8
0
0
2 3.5
6
8 10 12 14 16 18 20 MHz 24
f_OSC
Figure 6-46
Minimum A/D Conversion Time in Relation to System Clock
Semiconductor Group
6-103