$data = array(

    array('佐藤', '東京都', '29歳'),

    array('田中', '千葉県', '31歳'),

    array('鈴木', '北海道', '54歳')

  );

  

  header('Content-Type: application/octet-stream');

  header('Content-Disposition: attachment; filename=data.csv');

  

  $stream = fopen('php://output', 'w');

  foreach($data as $row){

    fputcsv($stream, $row);

  }