diff --git a/artiq/coredevice/phaser.py b/artiq/coredevice/phaser.py
index bb3cfd6df..c6e614a01 100644
--- a/artiq/coredevice/phaser.py
+++ b/artiq/coredevice/phaser.py
@@ -1144,6 +1144,10 @@ class PhaserChannel:
 
         Gains are given in units of output full per scale per input full scale.
 
+        .. note:: Due to inherent constraints of the fixed point datatypes and IIR
+        filters, the setpoint resolution depends on the selected gains. This is
+        especially the case for low ``ki`` gains.
+
         The transfer function is (up to time discretization and
         coefficient quantization errors):