diff --git a/src/finn/custom_op/fpgadataflow/channelwise_op_batch.py b/src/finn/custom_op/fpgadataflow/channelwise_op_batch.py
index ad91013a2e796a60df30bd42595d41e46c1c2ee6..3cd6a7dfdbb2db7df08e1c726ee522b3c2ed20a0 100644
--- a/src/finn/custom_op/fpgadataflow/channelwise_op_batch.py
+++ b/src/finn/custom_op/fpgadataflow/channelwise_op_batch.py
@@ -56,7 +56,7 @@ def get_smallest_possible(vals):
     for v in vals:
         assert int(v) == v, "Error float value"
 
-    for k in DataType.__members__:
+    for k in DataType.get_accumulator_dt_cands():
         dt = DataType[k]
 
         if dt in [DataType["BIPOLAR"], DataType["TERNARY"], DataType["FLOAT32"]]:
diff --git a/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py b/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
index 4ab9c8fe27fce2a71cd9e21e6a94c1eb706cc47a..8ac3a705ba1db6a9baf2df1f25b516e3dba42751 100644
--- a/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
+++ b/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
@@ -1251,7 +1251,7 @@ class InferChannelwiseLinearLayer(Transformation):
         for v in vals:
             assert int(v) == v, "Error float value"
 
-        for k in DataType.__members__:
+        for k in DataType.get_accumulator_dt_cands():
             dt = DataType[k]
 
             if dt in [DataType["BIPOLAR"], DataType["TERNARY"], DataType["FLOAT32"]]: