diff --git a/boards/samd21-xpro/include/periph_conf.h b/boards/samd21-xpro/include/periph_conf.h
index 2bcc8f0e2ee4..3acb45a016bc 100644
--- a/boards/samd21-xpro/include/periph_conf.h
+++ b/boards/samd21-xpro/include/periph_conf.h
@@ -64,8 +64,8 @@ extern "C" {
  *
  * @{
  */
-#define CLOCK_SRC                   (CLOCK_USE_8MHZ)
-#define CLOCK_CORECLOCK             (8000000U)
+#define CLOCK_SRC                   (CLOCK_USE_PLL)
+#define CLOCK_CORECLOCK             (48000000U)
 /** @} */
 
 /**