diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 355e9cad680d..4706df20191b 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -25,7 +25,7 @@
  * Byte threshold to limit memory consumption for flip buffers.
  * The actual memory limit is > 2x this amount.
  */
-#define TTYB_DEFAULT_MEM_LIMIT	65536
+#define TTYB_DEFAULT_MEM_LIMIT	(640 * 1024UL)
 
 /*
  * We default to dicing tty buffer allocations to this many characters