Datasheet

MIC2288
DS20006034B-page 12  2018 Microchip Technology Inc.
5.4.2 OUTPUT CAPACITOR
Output capacitor selection is also a trade-off between
performance, size, and cost. Increasing output
capacitance will lead to an improved transient
response, but also an increase in size and cost. X5R or
X7R dielectric ceramic capacitors are recommended
for designs with the MIC2288. Y5V values may be used
but to compensate their drift over temperature, more
capacitance is required. The following table shows the
recommended ceramic (X5R) output capacitor value
vs. output voltage.
5.4.3 DIODE SELECTION
The MIC2288 requires an external diode for operation.
A Schottky diode is recommended for most
applications due to their lower forward voltage drop and
reverse recovery time. Ensure the diode selected can
deliver the peak inductor current and the maximum
reverse voltage is rated greater than the output voltage.
5.4.4 INPUT CAPACITOR
A minimum 1F ceramic capacitor is recommended for
designing with the MIC2288. Increasing input
capacitance will improve performance and greater
noise immunity on the source. The input capacitor
should be as close as possible to the inductor and the
MIC2288, with short traces for good noise
performance.
5.4.5 FEEDBACK RESISTORS
The MIC2288 utilizes a feedback pin to compare the
output to an internal reference. The output voltage is
adjusted by selecting the appropriate feedback resistor
network values. The R2 resistor value must be less
than or equal to 5 k (R2  5k).The desired output
voltage can be calculated as follows:
EQUATION 5-3:
TABLE 5-1: OUTPUT CAPACITOR
SELECTION
Output Voltage
Recommended Output
Capacitance
<6V 22 µF
<16V 10 µF
<34V 4.7 µF
V
OUT
V
REF
R1
R2
------ -
1+


=
Where:
V
REF
= 1.24V