diff --git a/gvtt/__init__.py b/gvtt/__init__.py
index 44ab627..85b1a91 100644
--- a/gvtt/__init__.py
+++ b/gvtt/__init__.py
@@ -45,7 +45,7 @@
 
 LAYER_VIEWS = None  # LayerViews(filepath=PATH.klayout_yaml)
 
-pdk = Pdk(
+PDK = Pdk(
     name="VTT-3umSOI",
     cells=cells,
     cross_sections=cross_sections,
@@ -65,11 +65,11 @@
     {"cross_section": "strip", "settings": {"width": 3.0}},
 ]
 
-pdk.activate()
+PDK.activate()
 __version__ = "0.0.2"
 
 if __name__ == "__main__":
     # layer_views = LayerViews(filepath=PATH.lyp_yaml)
     # layer_views.to_lyp(PATH.lyp)
 
-    print(pdk.name)
+    print(PDK.name)
diff --git a/pyproject.toml b/pyproject.toml
index 5437f76..72b56a5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ classifiers = [
   "Operating System :: OS Independent"
 ]
 dependencies = [
-  "gdsfactory[cad]>=7.1.1,<7.2.0"
+  "gdsfactory[cad]==7.3.1"
 ]
 description = "gdsfactory VTT PDK"
 keywords = ["python"]