diff --git a/examples/device/usbtmc/src/usb_descriptors.c b/examples/device/usbtmc/src/usb_descriptors.c
index 50545676..2336266b 100644
--- a/examples/device/usbtmc/src/usb_descriptors.c
+++ b/examples/device/usbtmc/src/usb_descriptors.c
@@ -80,10 +80,11 @@ uint8_t const * tud_descriptor_device_cb(void)
      TUD_USBTMC_BULK_DESCRIPTORS(/* OUT = */0x01, /* IN = */ 0x81, /* packet size = */USBTMCD_MAX_PACKET_SIZE)
 
 #if CFG_TUD_USBTMC_ENABLE_INT_EP
-// Interrupt endpoint should be 2 bytes on a FS USB link
+// USBTMC Interrupt xfer always has length of 2, but we use epMaxSize=8 for
+//  compatibility with mcus that only allow 8, 16, 32 or 64 for FS endpoints
 #  define TUD_USBTMC_DESC(_itfnum) \
      TUD_USBTMC_DESC_MAIN(_itfnum, /* _epCount = */ 3), \
-     TUD_USBTMC_INT_DESCRIPTOR(/* INT ep # */ 0x82, /* epMaxSize = */ 2, /* bInterval = */16u )
+     TUD_USBTMC_INT_DESCRIPTOR(/* INT ep # */ 0x82, /* epMaxSize = */ 8, /* bInterval = */16u )
 #  define TUD_USBTMC_DESC_LEN (TUD_USBTMC_IF_DESCRIPTOR_LEN + TUD_USBTMC_BULK_DESCRIPTORS_LEN + TUD_USBTMC_INT_DESCRIPTOR_LEN)
 
 #else