ncp1536 ON Semiconductor, ncp1536 Datasheet - Page 5

• Manufacturer Part Number: ncp1536
• Description: 3.0 A, Step-down Switching Regulator
• Manufacturer: ON Semiconductor

circuit board is very important. Rapidly switching currents
associated with wiring inductance, stray capacitance and
parasitic inductance of the printed circuit board traces can
generate
electromagnetic interferences (EMI) and affect the desired
operation. As indicated in the Figure 2, to minimize
inductance and ground loops, the length of the leads
indicated by heavy lines should be kept as short as possible.
ground plane construction should be used.
As in any switching regulator, the layout of the printed
For best results, single−point grounding (as indicated) or
voltage
7.0 V − 20 V
Unregulated
DC Input
transients
C
100 mF
in
which
V
in
1
3
can
NCP1536
GND
PCB LAYOUT GUIDELINES
Figure 2. Typical Test Circuit
generate
5
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V out + V
R2 + R1
Where V
between 1.0 k and 5.0 k
ON/OFF
NCP1536
2
4
Output
Feedback
ref
ref
5
= 1.23 V, R1
V out
V
ref
1.0 ) R2
(emitter of the internal switch) of the NCP1536 should be
kept to a minimum in order to minimize coupling to sensitive
circuitry.
important to keep the sensitive feedback wiring short. To
assure this, physically locate the programming resistors near
to the regulator.
– 1.0
On the other hand, the PCB area connected to the Pin 2
Another sensitive part of the circuit is the feedback. It is
100 mH
D1
MBR360
R1
L1
C
1000 mF
out
R2
R1
5.0 V
Load
V
out