diff --git a/examples/parametertree.py b/examples/parametertree.py
index af1cf3ab..89932ed6 100644
--- a/examples/parametertree.py
+++ b/examples/parametertree.py
@@ -82,7 +82,7 @@ params = [
         {'name': 'Units + SI prefix', 'type': 'float', 'value': 1.2e-6, 'step': 1e-6, 'siPrefix': True, 'suffix': 'V'},
         {'name': 'Limits (min=7;max=15)', 'type': 'int', 'value': 11, 'limits': (7, 15), 'default': -6},
         {'name': 'Int suffix', 'type': 'int', 'value': 9, 'suffix': 'V'},
-        {'name': 'DEC stepping', 'type': 'float', 'value': 1.2e6, 'dec': True, 'step': 1, 'siPrefix': True, 'suffix': 'Hz'},
+        {'name': 'DEC stepping', 'type': 'float', 'value': 1.2e6, 'dec': True, 'step': 1, 'minStep': 1.0e-12, 'siPrefix': True, 'suffix': 'Hz'},
         
     ]},
     {'name': 'Save/Restore functionality', 'type': 'group', 'children': [
diff --git a/pyqtgraph/widgets/SpinBox.py b/pyqtgraph/widgets/SpinBox.py
index b1c72668..88cc02a6 100644
--- a/pyqtgraph/widgets/SpinBox.py
+++ b/pyqtgraph/widgets/SpinBox.py
@@ -223,6 +223,10 @@ class SpinBox(QtGui.QAbstractSpinBox):
 
             if 'format' not in opts:
                 self.opts['format'] = asUnicode("{value:d}{suffixGap}{suffix}")
+
+        if self.opts['dec']:
+            if self.opts.get('minStep') is None:
+                self.opts['minStep'] = self.opts['step']
         
         if 'delay' in opts:
             self.proxy.setDelay(opts['delay'])