S42
Hardware User Guide
1VV0301303 Rev. 11
Page 33 of 85
2021-05-06
Not Subject to NDA
F
SAMPLE
< 1/ (t
ACQ
+ t
CONV
) must be maintained
The time necessary to load C
SAMPLE
with sufficient preciseness to V
SOURCE
depends on the
values of C
SAMPLE
, known 2,5pF typ., and the source resistance of V
SOURCE
, e.g. a
potentiometer.
Therefore the max. allowed source resistance of V
SOURCE
depends on the programmed
acquisition time.
TACQ /µs
Max. resistance VSOURCE /k
Ω
3
10
5
40
10
100
15
200
20
400
40
800
Table 9: T
ACQ
versus R(V
SOURCE
) max.
Firmware ADC/TWI
The FW ADC/TWI uses a fix acquisition time of 15µs and increases the resolution by
oversampling. The sample rate is programmable via at-command in the range of 5ms to
2000ms. Therefore, this ADC is meant for measuring DC sources. The max. allowed
change rate is the max.
∆
V of a 100Hz sine wave with full swing input amplitude.
Please refer to [9] for programming the ADC and to Chapter 4.4 Application Specific
ADC/TWI Pin Configuration for ADC module pin mapping.
Firmware ADC/LUA
The FW ADC/LUA uses a fix acquisition time of 3µs and increases the resolution by
oversampling.
for programming the ADC and to Chapter 4.5 Application Specific
ADC/LUA Pin Configuration for ADC/LUA module pin mapping.
