Micrel, Inc.
MIC24055 Evaluation Board
February 11, 2013
2
Revision 1.0
Output Voltage
The output voltage on the MIC24055 evaluation board is
adjustable. It is set by adjusting the feedback resistors, as
illustrated in Equation 1:
+
×
=
BOTTOM
FB
OUT
R
R4
1
V
V
Eq. 1
where V
FB
= 0.8V and R
BOTTOM
is one of the R5, R6, R7,
R8, R9, R10, R11, R12 which corresponds to 0.9V, 1.0V,
1.2V, 1.5V, 1.8V, 2.5V, 3.3V, or 5V. Leaving the R
BOTTOM
open gives a 0.8V output voltage. The output voltage
above is set at the factory for a 1.8V output, but it can
easily be changed by moving the jumper to a respective
position to get an indicated voltage on the board. If a
desired voltage is not shown on the board, it is easily
modified by removing R
BOTTOM
and replacing it with the
values that yield the desired output voltage. Once R4 is
selected, R
BOTTOM
can be
calculated using Equation 2:
FB
OUT
FB
BOTTOM
V
V
V
R4
R
−
×
=
Eq. 2
For V
FB
= 0.8V, as in Equation 3:
0.8V
V
0.8V
R4
R
OUT
BOTTOM
−
×
=
Eq. 3
The output voltage should not be set to exceed 5V due to
the 6.3V rating of the output capacitor and limitation on line
regulation. Please refer to the “Setting the Output Voltage”
and Ripple Injection” subsections in the
Application
Information
section of the MIC24055 data sheet for more
detailed information.
