MP1522 – 25V STEP-UP CONVERTER IN A SOT23-5 PACKAGE
Diode
The high switching frequencies of the MP1522
require the use of fast recovery or Schottky
barrier diodes. In low voltage applications
Schottky barrier diodes are recommended for
maximum efficiency. The reverse breakdown
voltage should be approximately 1.5X the
output voltage.
Printed Circuit Board Layout
The printed circuit board layout is important in
order to minimize noise and prevent erratic
operation. Keep the ground leads short and
robust with minimum lead lengths between the
input and output capacitors and ground. Place
the feedback resistive voltage divider as close
to FB as possible to prevent switching noise
injection into FB. The use of surface mount
capacitors with their low ESL is required to
minimize noise at the MP1522. Use separate
power and quiet ground planes connected
together at a single point whenever possible to
minimize.ground.bounce.
V
IN
3.3V
Table 1—Output Current vs. Input Voltage
V
IN
(V)
3.3
3.3
3.3
3.3
5
5
5
10
10
10
V
OUT
(V)
5
12
18
25
12
18
25
12
18
25
I
OUT
(mA)
67
28
15
10
44
32
19
122
75
51
OFF ON
4
EN
SW
1
5
3
D1
RB751
C2
1nF
V
OUT
20V
MP1522
2
GND
BIAS
FB
Figure 2—Typical Boost Application
MP1522 Rev. 2.0
9/1/2006
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5
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