XYZ tiles

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/ol3/3.7.0/ol.js"></script>
<body>
	<div id="mapDiv"></div>
</body>

CSS

html, body, #mapDiv {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}

JavaScript

// Base layer
  var base = new ol.layer.Tile({
    source: new ol.source.XYZ({
      minZoom: 0,
      maxZoom: 5,
			tileSize: 256,	
      url: 'http://tileserver.maptiler.com/nasa/{z}/{x}/{y}.jpg'
    })
  });

  // Map layer
  var map = new ol.Map({
    target: 'mapDiv',
    layers: [base],
    view: new ol.View({
      center: ol.proj.transform([0, 0], 'EPSG:4326', 'EPSG:3857'), 		// EPSG:4326 -> EPSG:3857
      zoom: 0,
      minZoom: 0,
      maxZoom: 10
    })
  });