lm2575-5 ON Semiconductor, lm2575-5 Datasheet - Page 7

• Manufacturer Part Number: lm2575-5
• Description: 1.0 A, Adjustable Output Voltage, 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 14, to minimize
inductance and ground loops, the length of the leads
indicated by heavy lines should be kept as short as possible.
For best results, single−point grounding (as indicated) or
ground plane construction should be used.
As in any switching regulator, the layout of the printed
voltage
Unregulated
8.0 V - 40 V
DC Input
Unregulated
8.0 V - 40 V
DC Input
transients
V
in
+
-
+
-
C
100 mF/50 V
in
which
V
C
100 mF/50 V
in
1
in
V
3
in
1
Adjustable
Adjustable Output Voltage Versions
GND
LM2575
can
3
Figure 14. Typical Test Circuit
PCB LAYOUT GUIDELINES
5.0 Output Voltage Versions
LM2575−5
GND
5
generate
V out + V
R2 + R1
Where V
between 1.0 kW and 5.0 kW
http://onsemi.com
ON/OFF
5
2
4
Output
Feedback
ref
ON/OFF
ref
= 1.23 V, R1
V out
V
7
2
ref
4
Output
Feedback
1 ) R2
(emitter of the internal switch) of the LM2575 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, when using the adjustable version of the
LM2575 regulator.
1
330 mH
D1
1N5819
R1
On the other hand, the PCB area connected to the Pin 2
Another sensitive part of the circuit is the feedback. It is
L1
D1
1N5819
330 mH
L1
C
330 mF
/16 V
out
C
330 mF
/16 V
out
Regulated
R2
R1
Output
Load
V
out
Regulated
Output
Load
V
out