Key Specs
| Spec | Value | Condition | Source |
|---|---|---|---|
| Mode | Continuous Conduction (CCM) | Digi-Key | |
| Switching Frequency (Typ) | 22kHz ~ 123kHz | Digi-Key | |
| Voltage Supply | 10.2V ~ 15V | Digi-Key | |
| Operating Temperature Range | -40°C ~ 150°C (TJ) | Digi-Key | |
| Mounting Type | Through Hole | Digi-Key | |
| Package Case | 16-SSIP, 13 Leads, Exposed Pad, Formed Leads | Digi-Key | |
| Supplier Device Package | eSIP-16D | Digi-Key |
When To Use
Use the PFS7724H in applications requiring continuous conduction mode (CCM) power factor correction with high efficiency (>95%) and high power factor (>0.95 min), such as:
- Industrial Power Supplies: Where steady-state input voltage up to 305 VAC and peak input voltage up to 410 VAC are expected, and output power up to 385 W (high-line packages) is required.
- Consumer Electronics with Universal Input: Benefiting from the wide operating frequency range (22 kHz to 123 kHz) that simplifies EMI filter design.
- High-Power LED Drivers and Motor Drives: Where precise voltage monitoring and protection thresholds are critical, and device junction temperature can reach up to 150 °C.
Do not use the PFS7724H for:
- Low Power or Burst Mode Applications: The device’s continuous conduction mode and minimum switching frequency of 22 kHz make it unsuitable for low power or burst-mode designs. Instead, use a device optimized for discontinuous conduction mode (DCM) or burst mode.
- Applications Requiring Switching Frequencies Above 500 kHz: The maximum switching frequency is 500 kHz; designs requiring higher frequencies should use a different controller.
- Surface Mount Only Designs: The PFS7724H is through-hole mounted (16-SSIP package), so for compact surface mount applications, select a device with a suitable SMD package.
When Not To Use
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High-frequency DC-DC conversion > 500 kHz: The PFS7724H’s maximum switching frequency of 123 kHz is insufficient for applications requiring high-frequency switching to minimize magnetics size. Use a high-frequency buck controller instead to meet switching frequency demands.
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Battery-powered IoT sensor with ultra-low standby current: The typical no-load consumption is <60 mW, too high for μA-level sleep currents in battery-powered designs. Use a low-IQ PFM buck to reduce quiescent current and extend battery life.
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Galvanically isolated power supplies: The PFS7724H is designed for non-isolated PFC front-ends and does not support isolation features. Use an isolated flyback controller for applications requiring galvanic isolation between input and output.
Application Notes
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The switching node (SW) must be kept as compact as possible with low inductance and low parasitic capacitance traces to minimize EMI and ringing; avoid long PCB runs around the SW pin to reduce voltage overshoot.
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the FB pin and the REF pin are noise-sensitive feedback and reference pins; route their traces away from noisy switching nodes and provide local decoupling capacitors (0.1 mF ±20%) close to REF to stabilize the reference voltage.
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The exposed pad on the 16-SSIP package must be soldered to a large copper area connected to PCB ground and thermal vias to optimize heat dissipation and maintain junction temperature below 150 °C.
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The voltage monitor pin divider resistors should be matched to 8 MΩ ±1% nominal to ensure proper line sensing accuracy and overcurrent protection thresholds.
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Guard rings or ground pours around signal ground pin (G) traces help minimize ground noise coupling into sensitive internal circuitry; keep signal ground separate from power ground until a single star point near the exposed pad.
Gotchas
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Incorrect Reference Pin Capacitor Value:
Mistake: Using a reference pin capacitor significantly larger than the specified maximum 1.0 µF ±20%.
Failure: Causes instability in the internal voltage reference, leading to erratic feedback and output voltage regulation issues.
Fix: Use the recommended 0.1 µF ±20% capacitor on the REF pin to maintain stable operation. -
Using Diodes with High Reverse Recovery Time:
Mistake: Selecting diodes without low reverse recovery time and charge for the boost diode.
Failure: Results in excessive switching losses, increased EMI, and potential device overheating due to hard switching in CCM.
Fix: