Add CDATA addChild node SimpleXML PHP

Question

at the following script I have to add CDATA to "address" child

if(ISSET($_POST['insert'])){
    if(file_exists("foo.xml")){
        $members = simplexml_load_file('foo.xml');
        $member = $members->addChild('member');
        $member->addChild('name', $_POST['name']);
        $member->addChild('address', $_POST['address']);
        file_put_contents('member.xml', $members->asXML());
        header('location:index.php');
    }
}

This generate the following result:

<?xml version="1.0"?>
 <members>
 <member>
 <name>John</name>
 <address>New York</address>
 </member>
 </members>

I have to add CDATA and create he code below:

<?xml version="1.0"?>
<members>
<member>
<name>John</name>
<address><![CDATA[New York]]></address>
</member>
</members>

Thank you!