C8051F980-C-GM Datasheet, PDF (73/325 Pages) Silicon Laboratories – Ultra Low Power, 8-2 kB Flash, Capacitive Sensing MCU

C8051F99x-C8051F98x
Table 5.1. Representative Conversion Times and Energy Consumption for the SAR
ADC with 1.65 V High-Speed VREF
Normal Power Mode
Low Power Mode
8 bit
10 bit
12 bit
8 bit
10 bit
12 bit
Highest nominal
SAR clock
frequency
8.17 MHz 8.17 MHz
(24.5/3) (24.5/3)
6.67 MHz
(20.0/3)
4.08 MHz 4.08 MHz
(24.5/6) (24.5/6)
4.00 MHz
(20.0/5)
Total number of
11
conversion
clocks required
13
52 (13 x 4)
11
13
52 (13*4)
Total tracking
time (min)
1.5 µs
1.5 µs
4.8 µs
(1.5+3 x 1.1)
1.5 µs
1.5 µs
4.8 µs
(1.5+3 x 1.1)
Total time for one
conversion
2.85 µs
3.09 µs
12.6 µs
4.19 µs 4.68 µs
17.8 µs
ADC Throughput ^{351 ksps 323 ksps}
79 ksps
238 ksps 214 ksps
56 ksps
Energy per
conversion
8.2 nJ
8.9 nJ
36.5 nJ
6.5 nJ
7.3 nJ
27.7 nJ
Note: This table assumes that the 24.5 MHz precision oscillator is used for 8- and 10-bit modes, and the 20 MHz
low power oscillator is used for 12-bit mode. The values in the table assume that the oscillators run at their
nominal frequencies. The maximum SAR clock values given in Table 4.10 allow for maximum oscillation
frequencies of 25.0 MHz and 22 MHz for the precision and low-power oscillators, respectively, when using
the given SAR clock divider values. Energy calculations are for the ADC subsystem only and do not include
CPU current. 12-bit mode is only available on C8051F980/6 and C8051F990/6 devices.
Rev. 1.2
73