About an AMP code

Hi, I just test the code below:

<amp-ad width="750" height="429"
    type="adplugg"
    data-access-code="A48XXX45"
    data-zone="reklama_w_artykule_amp_"
></amp-ad>

(BTW it took me a lot of time to get that characters <> in your examples at the beginning and the end command data-zone and data-access-code are inproper ;-) )

Back to the point...Does it necessary to specific width and height for the ad? In non AMP ads/zone/placement there is only a maximum size for the ad required, and its works fine becouse, as I noticed this ads can resize depending on device.

With an AMP code, when I put the same size of ad, on mobile it apears to biger than screen.

I'm not sure if I made my self clear. Hope you get what I mean. If note I try to make a screen shot