diff --git a/verilog/rtl/pads.v b/verilog/rtl/pads.v
index 25bc89f..6813066 100644
--- a/verilog/rtl/pads.v
+++ b/verilog/rtl/pads.v
@@ -11,6 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
 
 // `default_nettype none
 `ifndef TOP_ROUTING