TI had a note to create DAC signals using PWM.http://www.ti.com/lit/ug/tidu027/tidu027.pdf
Whereas I also found an article that says
"High current, high frequency PWM signals are notorious for creating and radiating electromagnetic interference (EMI and RFI).
Consequently, if you use PWM currents for controlling power devices, you should make your connections in a way that minimizes or limits the radiated noise.
In general, single point grounding and using shielded twisted pair cable are essential to prevent EMI or mitigate PWM noise."
Why does high current / high frequency PWM signals can create EMIs and signal ground noise? It looks like this is related to electromagnetics, but I cannot clearly explain the reason.
Does this also mean that PWM based buck converter, like the LM3671/-Q1 2-MHz, 600-mA Step-Down DC-DC Converter, can create EMI to nearby circuits? It makes me feel like I have to populate the Bluetooth/Wi-Fi microcontroller far away from this buck converter.
In the LM3671 datasheet, it says
http://www.ti.com/lit/ds/symlink/lm3671.pdf
- 2-MHz PWM Fixed Switching Frequency (Typical)
- Automatic PFM-PWM Mode Switching
