diff --git a/include/mbedtls/psa_util.h b/include/mbedtls/psa_util.h
index a5f09a4..9294d29 100644
--- a/include/mbedtls/psa_util.h
+++ b/include/mbedtls/psa_util.h
@@ -188,7 +188,7 @@
  *
  * \param       bits        Size of each coordinate in bits.
  * \param       raw         Buffer that contains the signature in raw format.
- * \param       raw_len     Length of \p raw in bytes. This must be
+ * \param       raw_len     Length of \p raw in bytes. This must be at least
  *                          PSA_BITS_TO_BYTES(bits) bytes.
  * \param[out]  der         Buffer that will be filled with the converted DER
  *                          output. It can overlap with raw buffer.