diff --git a/artiq/gateware/targets/kc705_sma_spi.py b/artiq/gateware/targets/kc705_sma_spi.py
index 818a5c4a2..cbdf74a52 100644
--- a/artiq/gateware/targets/kc705_sma_spi.py
+++ b/artiq/gateware/targets/kc705_sma_spi.py
@@ -75,7 +75,7 @@ _sma_spi = [
         Subsignal("cs_n", Pins("Y24")),  # user_sma_gpio_n
         Subsignal("mosi", Pins("L25")),  # user_sma_clk_p
         Subsignal("miso", Pins("K25")),  # user_sma_clk_n
-        IOStandard("LVCMOS33")),
+        IOStandard("LVCMOS25")),
 ]