SAB80C515A-5 Datasheet, PDF (36/108 Pages) Siemens Semiconductor Group – 8-Bit CMOS Single-Chip Microcontroller Family

On-Chip Peripheral Components
5.1 10-Bit A/D-Converter
In the SAB 80C515A a new high performance/high speed 8-channel 10-bit A/D-Converter is
implemented. Its successive approximation technique provides 7 µs conversion time
(f_OSC = 16 MHz). The conversion principle is upward compatible to the one used in the SAB 80C515.
The major components are shown in figure 5-1.
The comparator is a fully differential comparator for a high power supply rejection ratio and very low
offset voltages. The capacitor network is binary weighted providing 10-bit resolution.
The table below shows the sample time T_S and the conversion time T_C (including T_S), which depend
on f_OSC and the selected prescaler (see also Bit ADCL in SFR ADCON 1).
f_osc [MHz]
12
16
18
Prescaler
÷8
÷ 16
÷8
÷ 16
÷8
÷ 16
f_ADC [MHz]
1.5
0.75
2.0
1.0
–
1.125
T_S [µs]
2.67
5.33
2.0
4.0
–
3.555
T_C [µs]
(incl. T_S)
9.33
18.66
7.0
14.0
–
12.4
Semiconductor Group
5-3