NCP1219PRINTGEVB
http://onsemi.com
15
Figure 29. Startup Waveforms Showing Soft
−
Start Behavior; C1 = V
out
, C4 = V
CS
/20
Board Layout
The evaluation board is built using a double sided FR4
board. Through hole components are placed on the top layer
and surface mount components on the bottom layer. The
board is constructed using 2 oz copper.
During the layout process care was taken to:
1. Minimize trace length, especially for high current
loops.
2. Use wide traces for high current connections.
3. Use a single ground connection.
4. Keep sensitive nodes away from noisy nodes such
as the drain of the power switch.
5. Place decoupling capacitors close to the pins of IC.
6. Sense output voltage at the output terminal to
improve load regulation.
Figure 30 shows the top layer of the PC board, including
the silkscreen, copper, and soldermask.
