Bypassing the ICs supply (VCC) and reference voltage (VREF) pins with a 0.1-µF to 1-µF ceramic capacitor to ground is important. The capacitors must be placed as close to the actual pin connections as possible for optimal noise filtering. A second, larger filter capacitor can also be required in offline applications to hold the supply voltage (VCC) above the UVLO turnoff threshold during start-up.

To prevent false triggering due to leading edge noises, an RC current sense filter can be required on ISENSE. Keep the time constant of the RC filter well below the minimum on-time pulse width.

Schottky diodes can be necessary on the OUTPUT pin to prevent overshoot and undershoot due to the high impedance to the supply rail and to ground, respectively. A bleeder resistor, placed between the gate and the source of the MOSFET must be used to prevent activating the power switch with extraneous leakage currents during undervoltage lockout.

To prevent noise problems with high-speed switching transients, bypass VREF to ground with a ceramic capacitor close to the IC package. A minimum of 0.1-µF ceramic capacitor is required. Additional VREF bypassing is required for external loads on the reference. An electrolytic capacitor can also be used in addition to the ceramic capacitor.