MP2303DN Monolithic Power Systems, MP2303DN Datasheet - Page 10

• Manufacturer Part Number: MP2303DN
• Description: 3A, 28V, 340khz Synchronous Rectified Step-down Converter
• Manufacturer: Monolithic Power Systems

In this case, a third pole set by the optional
compensation
compensation
compensate the effect of the ESR zero on the
loop gain. This pole is located at:
The goal of compensation design is to shape
the converter transfer function to get a desired
loop gain. The system crossover frequency
where the feedback loop has the unity gain is
important.
Lower crossover frequencies result in slower
line and load transient responses, while higher
crossover frequencies could cause system
instability. A good rule of thumb is to set the
crossover frequency to approximately one-tenth
of the switching frequency. Switching frequency
for the MP2303 is 340KHz, so the desired
crossover frequency is 34KHz.
Table 3 lists the typical values of compensation
components for some standard output voltages
with various output capacitors and inductors. The
values of the compensation components have
been optimized for fast transient responses and
good stability at given conditions.
MP2303 Rev. 0.92
5/2/2006
TM
f
P
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
resistor
3
capacitor
=
2
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
π
×
C
1
6
(R3)
×
R
(C6)
3
is
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
and
used
© 2006 MPS. All Rights Reserved.
www.MonolithicPower.com
the
to
Table 3—Compensation Values for Typical
V
1.8V
2.5V
3.3V
2.5V
3.3V
2.5V
3.3V
12V
12V
Output Voltage/Capacitor Combinations
1.8
5V
5V
5V
OUT
4.7µH
4.7µH -
6.8µH -
4.7µH -
6.8µH -
4.7µH -
6.8µH -
10µH -
15µH -
10µH -
10µH -
15µH -
6.8µH
4.7µH
6.8µH
6.8µH
10µH
15µH
22µH
10µH
15µH
10µH
15µH
22µH
L
100µF/100mΩ
47µF Ceramic
30mΩ ESR
30mΩ ESR
30mΩ ESR
30mΩ ESR
560µF Al.
560µF Al.
470µF Al.
220µF Al.
Ceramic
Ceramic
Ceramic
Ceramic
SP-CAP
SP-CAP
SP-CAP
SP CAP
22µFx2
22µFx2
22µFx2
100µF
47µF
47µF
47µF
C2
3.65kΩ
4.42kΩ
6.98kΩ
16.5kΩ
5.6kΩ
8.4kΩ
5.6kΩ
6.8kΩ
10kΩ
10kΩ
10kΩ
15kΩ
15kΩ
R3
10nF
5.6nF
8.2nF
4.7nF
3.3nF
1.8nF
2.2nF
3.3nF
2.2nF
2.2nF
8.2nF
12nF
10nF
C3
390pF
1.8nF
1.5nF
None
None
None
None
None
None
None
None
None
10
1nF
C6