W-6238 Datasheet, PDF (11/14 Pages) Copal Electronics – High Efficiency 10 LED Boost Converter

W-6238
BOARD LAYOUT
The W-6238 is a high-frequency switching regulator.
The traces that carry the high-frequency switching
current have to be carefully laid out on the board in
order to minimize EMI, ripple and noise in general.
The thicker lines on Figure 3 show the switching
current path. All these traces have to be short and
wide enough to minimize the parasitic inductance and
resistance. The loop shown on Figure 3 corresponds
to the current path when the W-6238 internal switch
is closed. On Figure 4 is shown the current loop, when
the W-6238 switch is open. Both loop areas should
be as small as possible.
Capacitor C1 has to be placed as close as possible to
the VIN pin and GND. The capacitor C2 has to be
connected separately to the top LED anode. A ground
plane under the W-6238 allows for direct connection
of the capacitors to ground. The resistor R1 must be
connected directly to the GND pin of the W-6238
and not shared with the switching current loops and
any other components.
W-6
Figure 3. Closed-switch Current Loop
W-6238
Figure 4. Open-switch Current Loop
Figure 5. Recommended PCB Layout
© NIDEC COPAL ELECTRONICS CORP.
11
Characteristics subject to change without notice
Doc. No. MD-5019 Rev. D