NCP1402
http://onsemi.com
17
Components Supplier
Parts Supplier Part Number Description Phone
Inductor, L1 Sumida Electric Co. Ltd. CD54−470L
Inductor 47 H / 0.72 A
(852)−2880−6688
Schottky Diode, D1 ON Semiconductor Corp. MBR0520LT1 Schottky Power Rectifier (852)−2689−0088
Output Capacitor, C2 KEMET Electronics Corp. T494D686K010AS
Low ESR Tantalum Capacitor
68 F / 10 V
(852)−2305−1168
Input Capacitor, C1 KEMET Electronics Corp. T491C106K016AS
Low Profile Tantalum Capacitor
10 F / 16 V
(852)−2305−1168
PCB Layout Hints
Grounding
One point grounding should be used for the output power
return ground, the input power return ground, and the device
switch ground to reduce noise as shown in Figure 62, e.g.:
C2 GND, C1 GND, and U1 GND are connected at one point
in the evaluation board. The input ground and output ground
traces must be thick enough for current to flow through and
for reducing ground bounce.
Power Signal Traces
Low resistance conducting paths should be used for the
power carrying traces to reduce power loss so as to improve
efficiency (short and thick traces for connecting the inductor
L can also reduce stray inductance), e.g.: short and thick
traces listed below are used in the evaluation board:
1. Trace from TP1 to L1
2. Trace from L1 to Lx pin of U1
3. Trace from L1 to anode pin of D1
4. Trace from cathode pin of D1 to TP2
Output Capacitor
The output capacitor should be placed close to the output
terminals to obtain better smoothing effect on the output
ripple.
1
3
GND
CE
2
OUT
NC
6
LX
5
NCP1402
On
TP1
TP4
TP2
TP3
V
in
GND
V
out
GND
C2
68 F/10 V
L1
47 H
JP1
Enable
C1
10 F/16 V
Off
D1
MBR0520LT1
Figure 62. NCP1402 Evaluation Board Schematic Diagram
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