HF900 Flyback Regulators Monolithic Power Systems (MPS) HF900 Flyback Regulators are offline switching regulators with an integrated 900V MOSFET. These regulators have a programmable fixed switching frequency up to 300kHz and a frequency jittering function to reduce the noise level. A single resistor programs the operating frequency externally. This allows the power supply's radiated energy to avoid interference with wireless communication. The peak-current-mode control provides superior transient response and eases loop compensation.