Can make a 50MHz PWM output?

[jhwan.2]

MCU : STM32H7, PB0 ​PWM CH2N

TIM1 CLK : 200MHz

Prescaler : 0

Counter Period : 3

Pulse : 2

GPIO Speed : Very High​

I'm testing a 50MHz PWM output.

And my test conditions are written at the top of this question.

As a result, I decided that a 50MHz PWM output was impossible.

This is because the square wave is distorted by the slew rate as shown in the attached picture.

However, the output buffer timing characteristics of the datasheet states that frequencies up to 220 MHz are possible.

So I leave a question to ask if I've missed anything.

thank you

[LCE]

Nice, okay, I oversaw the 500 MHz!

Still, you can do a lot of things wrong with the probe.

[Tesla DeLorean]

Looks like the wrong probe or setting.

Make sure to put it in 10x mode if you're using a 1x / 10x probe.

[jhwan.2]

Thanks for your reply.

I am using my own custom board.

So I think the key point is my probe.

[jhwan.2]

I'm used in x1 mode. and I don't know "Pf input" exactly.

I wonder what is your MCU Model

please let me know. thank you

[LCE]

In GHz-wireless times, measuring some 50 MHz seems like it must be so simple... :D

"pF" input: capacitance of the probe, a good probe has that printed on the probe or its connector.

And do NOT use x1 mode, all the probes I ever used have a much higher capacitance than in the 10:1 divider mode.

[AScha.3 · Accepted solution]

you have to use probe in 10:1 setting. (1:1 is useless with hi-speed cmos circuits ! )

cpu is stm32H743vit , at 200MHz core clk.

[jhwan.2]

The problem has been resolved.

Probe setup was the problem.

After setting to x10 mode, the waveform was checked normally.

thank you