MIC5206 Datasheet, PDF (7/8 Pages) Micrel Semiconductor – 150mA Low-Noise LDO Regulator

MIC5206
Resistor values are not critical because ADJ (adjust) has a
high input impedance, but for best results use resistors of
470kΩ or less. A capacitor from ADJ to ground provides
greatly improved noise performance.
V_OUT
47k
1
8
V_IN
2
7
Flag Output
2.2µF
3
(optional)
4
6
ADJ
5
R1 ^MIC5206BMM
R2
C_BYP
470pF
Figure 3. Ultra-Low-Noise
Adjustable Voltage Application
Figure 3 also includes a 470pF capacitor for lowest-noise
operation and shows EN (pin 7) connected to IN (pin 8) for an
application where enable/shutdown is not required. C_OUT =
2.2µF minimum. The error flag is shown with a 47kΩ pullup
resistor.
Thermal Considerations
Layout
The MIC5206-x.xBM5 (5-lead SOT-23 package) has the
following thermal characteristics when mounted on a single
layer copper-clad printed circuit board.
Multilayer boards having a ground plane, wide traces near the
pads, and large supply bus lines provide better thermal
conductivity.
Micrel
PC Board
θ_JA
Dielectric
FR4
220°C/W
Ceramic
200°C/W
SOT-23-5 Thermal Characteristics
The “worst case” value of 220°C/W assumes no ground
plane, minimum trace widths, and a FR4 material board.
The MIC5206-xxBMM (8-lead MSOP) has a thermal resis-
tance of 200°C/W when mounted on a FR4 board with
minimum trace widths and no ground plane.
PC Board
θ_JA
Dielectric
FR4
200°C
MSOP Thermal Characteristics
Nominal Power Dissipation and Die Temperature
The MIC5206-x.xBM5 at a 25°C ambient temperature will
operate reliably at over 450mW power dissipation when
mounted in the “worst case” manner described above. At an
ambient temperature of 40°C, the device may safely dissi-
pate over 380mW. These power levels are equivalent to a die
temperature of 125°C, the maximum operating junction tem-
perature for the MIC5206.
For additional heat sink characteristics, please refer to Micrel
Application Hint 17, “Calculating P.C. Board Heat Sink Area
For Surface Mount Packages”.
January 2000
7
MIC5206