Uploaded November 2025 | Updated September 2026, 1 hour ago
Identifying the cause and fixing it with an RC between OpAmp and ADC …
↓↓↓ Complete description, time index and links below ↓↓↓
In the previous video we tested our new ADC frontend (link below). The results were mostly OK. However, we saw increased noise on the voltage and we strong crosstalk on the current channel at higher voltages. So let’s solve that today.
We start by isolating the more pressing crosstalk problem, narrowing it down to a strong kickback respectively voltage droop at the ADC input when sampling. We solve this by adding an RC element between the op-amp and the ADC.
00:00 Intro – one annoyance and one problem left
01:13 Issues – noise annoyance, crosstalk problem
03:28 Testing (1) – for supply voltage issues
05:23 Testing (2) – ADC input voltage with multimeter
09:00 Testing (3) – ADC input voltage with oscilloscope
12:14 Problem – huge kickback when ADC is sampling
14:25 Textbook solution – RC between OpAmp and DAC
18:05 My solution – RC with grossly simplified math
24:28 Testing (4) - RC between OpAmp and DAC
28:16 Explanation – why the kickback caused crosstalk
29:41 Wrap-up – one problem left to solve, bye
Full Fly-by-Wire Electric Outboard youtube.com/playlist?list=PLwq-2MnM58FKvpYgFXgNCjlKo14L0KI16
Full Fly-by-Wire Electric Outboard (20): Redesign of ADC Frontend (3) youtu.be/afYJ_P5zH8A
Full Fly-by-Wire Electric Outboard (10): Water Intrusion Detection Circuit & Code youtu.be/7OSBXC-3OzY
Full Fly-by-Wire Electric Outboard (19): Chasing Noise & Intermittent Errors (2) youtu.be/WoKpIrfGIDM
Full Fly-by-Wire Electric Outboard (22): Redesign of ADC Frontend (4) youtu.be/NUJgexQXoV4
Bruce Carter, Texas Instruments, Buffer Op Amp to ADC Circuit Collection, Application Report SLOA098 – March 2002 ti.com/lit/pdf/sloa098
Alan Walsh, Analog Devices, Front-End Amplifier and RC Filter Design for a Precision SAR Analog-to-Digital Converter, Analog Dialogue 46-12, December 2012 analog.com/media/en/analog-dialogue/volume-46/number-4/articles/front-end-amp-and-rc-filter-design.pdf
Texas Instruments, Math behind the R-C component selection youtube.com/watch?v=g4V_OyDOG7k
#flybywire #electricoutboard #haswing #trollingmotor #outboardmotor #outboard #robertssmorgasbord
Identifying the cause and fixing it with an RC between OpAmp and ADC …
↓↓↓ Complete description, time index and links below ↓↓↓
In the previous video we tested our new ADC frontend (link below). The results were mostly OK. However, we saw increased noise on the voltage and we strong crosstalk on the current channel at higher voltages. So let’s solve that today.
We start by isolating the more pressing crosstalk problem, narrowing it down to a strong kickback respectively voltage droop at the ADC input when sampling. We solve this by adding an RC element between the op-amp and the ADC.
00:00 Intro – one annoyance and one problem left
01:13 Issues – noise annoyance, crosstalk problem
03:28 Testing (1) – for supply voltage issues
05:23 Testing (2) – ADC input voltage with multimeter
09:00 Testing (3) – ADC input voltage with oscilloscope
12:14 Problem – huge kickback when ADC is sampling
14:25 Textbook solution – RC between OpAmp and DAC
18:05 My solution – RC with grossly simplified math
24:28 Testing (4) - RC between OpAmp and DAC
28:16 Explanation – why the kickback caused crosstalk
29:41 Wrap-up – one problem left to solve, bye
Full Fly-by-Wire Electric Outboard youtube.com/playlist?list=PLwq-2MnM58FKvpYgFXgNCjlKo14L0KI16
Full Fly-by-Wire Electric Outboard (20): Redesign of ADC Frontend (3) youtu.be/afYJ_P5zH8A
Full Fly-by-Wire Electric Outboard (10): Water Intrusion Detection Circuit & Code youtu.be/7OSBXC-3OzY
Full Fly-by-Wire Electric Outboard (19): Chasing Noise & Intermittent Errors (2) youtu.be/WoKpIrfGIDM
Full Fly-by-Wire Electric Outboard (22): Redesign of ADC Frontend (4) youtu.be/NUJgexQXoV4
Bruce Carter, Texas Instruments, Buffer Op Amp to ADC Circuit Collection, Application Report SLOA098 – March 2002 ti.com/lit/pdf/sloa098
Alan Walsh, Analog Devices, Front-End Amplifier and RC Filter Design for a Precision SAR Analog-to-Digital Converter, Analog Dialogue 46-12, December 2012 analog.com/media/en/analog-dialogue/volume-46/number-4/articles/front-end-amp-and-rc-filter-design.pdf
Texas Instruments, Math behind the R-C component selection youtube.com/watch?v=g4V_OyDOG7k
#flybywire #electricoutboard #haswing #trollingmotor #outboardmotor #outboard #robertssmorgasbord
