Hi, I am trying to source smaller crystals (~2520) for USB support on the STM32F401. The best I can find so far is 1.5mA/V. I am calculating based on the information in AN2867 and the datasheet not mentioning Gm(as AN2867 requests), but a Max Gmcrit of 1mA/V. I assume that the max is a hard number and I am interpreting the table Table 37. HSE 4-26 MHz oscillator characteristics in the datasheet correctly. Would 12 or 16Mhz crystal still drive USB OK? I don't believe any other feature on the chip requires an ext crystal.