MCP1612-150I/MS Microchip Technology, MCP1612-150I/MS Datasheet - Page 13

• Manufacturer Part Number: MCP1612-150I/MS
• Description: Switching Converters, Regulators & Controllers 1.4MHz 1A Synch-Buck
• Manufacturer: Microchip Technology

Specifications of MCP1612-150I/MS

• Output Current: 1.0 A
• Mounting Style: SMD/SMT
• Package / Case: MSOP-8
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Solving for C:
There will also be some ripple voltage caused by the
ESR of the capacitor. The ripple is defined as follows.
EQUATION 5-7:
For this example:
5.2.4
For the Buck topology, the input current is pulled from
the source and the input capacitor in pulses. The size
of the input capacitor will determine the amount of cur-
rent pulled from the source. For most applications, a
10 µF ceramic capacitor connected between the
MCP1612 V
current pulses. Less capacitance can be used for
applications that have low source impedance. The
ripple current rating for ceramic capacitors are typically
very high due to their low loss characteristics. Low-cost
electrolytic capacitors can be used, but their ripple
current rating should not be exceeded.
5.2.5
The V
circuitry. A 10
unregulated input V
capacitor to ground to help isolate the V
switching noise.
 2004 Microchip Technology Inc.
Where:
I
V
V
C
CC
t
V
ESRRIPPLE
ESRRIPPLE
C
input is used to bias the internal MCP1612
= peak-to-peak ripple current
= output ripple voltage
= on-time of P-Channel MOSFET
INPUT CAPACITOR
V
V
V
V
IN
ESR = 8 m
CC
OUT
OUT
OUT
V
V
and P
V
I
C = 4.7 µF
C
C
C
resistor is recommended between the
t = 260 ns
ESRRIPPLE
INPUT
= 165 mA
= (260 ns x 165 mA)/4.7 µF
= 9.13 mV
= 8 m x 165 mA
= 1.32 mV
=
= 9.13 mV + 1.32 mV
= 10.45 mV
C
IN
GND
=
and V
V
I
C
is recommended to filter the
C
+ V
=
CC
---------- -
ESR
ESRRIPPLE
V
t
, along with a 0.1 µF
C
I
C
CC
pin from the
5.2.6
An internal transconductance error amplifier is used to
compensate the Buck converter. An external resistor
(R
and GND, are all that is needed to provide a high-
bandwidth loop.
Table 5-1 identifies values for R
Buck inductor, L, and output capacitor, C
TABLE 5-1:
5.3
The MCP1612 is capable of switching over 1A at
1.4 MHz. As with all high-frequency switching power
supplies, good board layout techniques are essential to
prevent noise generated by the switching power-train
from interfering with the sensing circuitry.
There are two ground pins (P
MCP1612 to separate the large-signal ground current
from the small-signal circuit ground. These two
grounds should be kept separate and only connected
together near the input bulk capacitor.
Care must also be taken to minimize the length and
loop area of the large-signal connections. Components
connected to this loop consist of the input bulk capaci-
tor, V
inductor and the output filter capacitor.
C
3.3 µH
2.2 µH
) and capacitor (C
IN
L
, P
Printed Circuit Board Layout
GND
COMPENSATION COMPONENTS
, and L
10.0 µF
4.7 µF
C
R
OUT
C
X
and C
C
pins of the MCP1612, the Buck
), connected between COMP
C
VALUES
MCP1612
GND
25 k
10 k
C
R
and C
C
and A
DS21921A-page 13
C
OUT
GND
for standard
1000 pF
1000 pF
, values.
C
) on the
C