diff --git a/Spreadsheet/Excel/Writer/Worksheet.php b/Spreadsheet/Excel/Writer/Worksheet.php
index aa20a4a..ca1e7fe 100644
--- a/Spreadsheet/Excel/Writer/Worksheet.php
+++ b/Spreadsheet/Excel/Writer/Worksheet.php
@@ -1362,7 +1362,7 @@ class Spreadsheet_Excel_Writer_Worksheet extends Spreadsheet_Excel_Writer_BIFFwr
         $row     = $match[2];
 
         // Convert base26 column string to number
-        $chars = split('', $col);
+        $chars = explode('', $col);
         $expn  = 0;
         $col   = 0;