A Schottky diode is chosen to remove the negative voltage from the clock signal after passing through the capacitor and also due to the functionality at higher switching frequencies. There are numerous possible Schottky diode packages with different voltage and current ratings. The Schottky diode used in this application is a BAT54W with a 30V V_RRM rating and 200mA I_F rating. When selecting a Schottky diode for this application, the main consideration is that the diode is rated for voltages higher than the maximum amplitude of the clock signal, has some potential overshoot, and has a similar current rating.