Key Specs

No verified spec values available.

When To Use

  1. 110 W universal input AC/DC power supply: The PFS7628H supports up to 305 VAC steady-state and 410 VAC abnormal input, making it ideal for universal input designs. Its >95% efficiency and >0.95 power factor ensure compliance with energy regulations, whereas a synchronous buck controller would fail due to lack of high-voltage AC input handling.

  2. High power factor LED driver at 350 W output: With a continuous power rating up to 350 W in the H package and typical output power capability reaching 385 W, the PFS7628H is suitable for high-power LED lighting requiring tight power factor correction. Using a lower power synchronous buck controller would risk thermal runaway under sustained high loads.

  3. Industrial 385 V output bus from 230 VAC input: The device’s maximum output voltage rating of 440 VDC and switching frequency range of 22–123 kHz support stable operation at higher output voltages common in industrial DC buses. Using a standard LDO regulator here would cause immediate thermal shutdown and insufficient voltage headroom.

When Not To Use

  1. Load currents above 18 A peak: The absolute maximum drain pin peak current is limited to 18.0 A. Applications needing higher current handling should use a high-current synchronous buck with external FETs to manage conduction losses and prevent device damage.

  2. Battery-powered devices requiring ultra-low quiescent current: The typical standby current of 320 mA is too high for battery-operated systems where μA-level sleep currents are crucial. Use a low-IQ PFM buck instead to maximize battery life.

  3. Applications requiring galvanic isolation: Since this device is a high-voltage non-isolated PFC controller, it is unsuitable for isolated power supplies. Select an isolated flyback topology controller to provide safety and noise immunity.

Application Notes

Gotchas

  1. [Power Good Function Disabled by Incorrect Threshold Pin Connection]: Connecting the POWER GOOD THRESHOLD pin directly to the REFERENCE pin disables the power good function, causing PG pin to remain high impedance regardless of output voltage. This leads to false indication of power status during system bring-up. Fix: Use a resistor divider from the output voltage to the POWER GOOD THRESHOLD pin, never connect it directly to the REFERENCE pin.

  2. [Output Capacitor ESR Impact on Stability]: Using output capacitors with excessively low ESR can cause instability or oscillations due to underdamped control loops, despite correct feedback divider ratios. Symptoms include output voltage ringing or erratic switching frequency. Fix: Use capacitors with moderate ESR as recommended and include small RC snubbers (e.g., C16 parallel to R19) to filter high-frequency noise.

  3. [Switching Frequency Variation Causing Timing Supervisor Errors]: The wide switching frequency range (22–123 kHz) and variable on/off times can cause timing supervisor misbehavior if external component values are not matched. This can lead to unintended soft shutdown or erratic PWM behavior. Fix: Verify timing components per datasheet recommendations and measure switching waveforms during prototype testing to confirm consistent on/off durations.

  4. [Thermal Derating Overlooked at High Line Voltages]: Although the device supports 305 VAC steady-state, operating near the maximum line voltage without adequate heat sinking can cause junction temperature to exceed 100 ºC max, triggering thermal shutdown. The thermal resistance varies by package and mounting quality. Fix: Perform thermal simulations with actual PCB layout and use recommended heat sink practices; verify junction temperature under worst-case line and load conditions.