WS3412 ProductDescription
Bypass Capacitor
FB Pin
The bypass capacitor on VCC pin should be as close as
possible to the VCC and GND pins.
The feedback resistor divider should be as close as
possible to the FB pin, and the trace must keeps away from
dynamic node of the inductor (DRAIN pin trace、the positive
pin and the negative pin of Vo trace), otherwise the FB pin
OVP function might have risk to be mis-triggered by the
system noise.
Ground Path
The power ground path for current sense resistor
should be short and wide, and it should be as close as
possible to the IC ground (pin 2), otherwise the LED output
current accuracy maybe affected. The IC signal ground for
COMP and FB components should be connected to the IC
GND pin with short traces and should be away from the
power ground path.
DRAIN Pin
To increase the copper area of DRAIN pin for better
thermal dissipation. However, too large copper area may
compromise EMI performance.
The Area of Power Loop
The material of PCB
The area of main current loop should be as small as
possible to reduce EMI radiation.
Avoid choosing the material that is easy to absorb the
moisture, just like paper copper-clad laminates.
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