diff --git a/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py b/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
index 88f5fa926f73d5cb1919a02c83153cb8d1894711..c6edd6104e48e88a9233777a29e41b60fbb588ca 100644
--- a/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
+++ b/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
@@ -1033,9 +1033,9 @@ class InferChannelwiseLinearLayer(Transformation):
         )
 
         if (0 <= vals).all():
-            return DataType.UINT32
+            return DataType.UINT64
         else:
-            return DataType.INT32
+            return DataType.INT64
 
     def apply(self, model):
         graph = model.graph