problem tcpdf data one on top of another

Hello I am presenting a problem when the pdf is generated by means of TCPDF and that is at the end of the page the letters are piling up

this is the code I'm using

$pdf->Ln($margin10);
$pdf->MultiCell(0, 5, 'Momentos Ejecución',1, 'C', $fill);
$pdf->MultiCell($w3, 7, "Fecha", 1, 'C', 1, 0, '', '', true, 0, false, true, 8, 'M');
$pdf->MultiCell($w3, 7, "Momentos", 1, 'C', 1, 0, '', '', true, 0, false, true, 7, 'M');
$pdf->MultiCell($w3, 7, 'Observaciones', 1, 'C', 1, 0, '', '', true, 0, false, true, 7, 'M');
$pdf->Ln();
$row1=mysqli_fetch_array($trazabilidadEjecucion);
if(count($row1)>0){
      $x=0; $y=0;
      foreach ($trazabilidadEjecucion as $row) {
        foreach ($row as $col) {
          if($pdf->GetY()>170){$pdf->AddPage();}
            $pdf->MultiCell($w3, 20, validarDatos($col), 1, 'C', 0, 0, '', '', true, 0, false, true,20, 'M');
        }
        $pdf->Ln();
      }
}else{
    $pdf->MultiCell(0, 10, "Sin Registros", 1, 'C', 0, 0, '', '', true, 0, false, true, 10, 'M');
    $pdf->Ln();
}