Micrel, Inc.

MIC47150

October 2009

9

M9999-102309-A

Application Information

Adjustable Regulator Design

The MIC47150 allows programming the output down to

0.9V. From the typical application in Figure 1, the output

voltage is set by placing a resistor divider network from

OUT to GND and is determined by the following

equation:

⎟

⎠

⎞

⎜

⎝

⎛

+

×

=

1

R2

R1

0.9

should not exceed 10kΩ. Larger values can cause

instability. The resistor values are calculated from the

above equation, resulting in the following:

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

−

×

=

1

0.9

V

R2

R1

OUT

EVB Layout

The MIC47150 evaluation board layout is shown in

Figures 2 and 3. For customer application boards,

recommended variations include using a static resistor

for R2 in place of the potentiometer as well as the

elimination of all test points and jumper options that are

included on the MIC47150 evaluation board.

Figure 2. MIC47150 EVB Top Layer

Figure 3. MIC47150 EVB Bottom Layer