MIC5159-1.8BM6 Micrel Semiconductor, MIC5159-1.8BM6 Datasheet - Page 9

• Manufacturer Part Number: MIC5159-1.8BM6
• Description: PROGRAMMABLE CURRENT LIMIT UCAP LDO REGULATOR CONTROLLER
• Manufacturer: Micrel Semiconductor

Layout Considerations
Input and output capacitor placement should be as close as
possible to the input and output, respectively. Trace resis-
tance between the current sense and the MOSFET source
should be minimized. Trace resistance will increase dropout
voltage. This is more of a factor at higher output currents.
Also, a minimum amount of distance between the gate pin, on
the MIC5159, and the P-Channel MOSFET gate is recom-
mended. A long trace can create a small parasitic inductor.
This, coupled to the gate capacitance of the MOSFET, can
create a high frequency tank circuit. A small 50 resistor in
series with the gate may be required to eliminate high-
frequency noise.
April 2004
MIC5159
9
Adjustable Regulator Design
The MIC5159 allows programming the output voltage any-
where between 1.235V to V
Figure 4. The resistor values are calculated by:
Where V
R1= R2
OUT
Figure 4. Adjustable Regulator Design
is the desired output voltage.
1.235
V
OUT
1
IN
. Two resistors are used. See
M9999-041204
Micrel