gistfile1.txt

header("Content-type: text/csv");  
header("Cache-Control: no-store, no-cache");  
header('Content-Disposition: attachment; filename="filename.csv"');

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

$test_data = $this->declarante_model->teste();

foreach( $test_data as $row ){  
    fputcsv($outstream, $row, ';', '"');  
}  

fclose($outstream);