GE866-QUAD Hardware User Guide
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Page 30 of 82
Mod. 0805 2011-07 Rev.2
6.3.
General Design Rules
The principal guidelines for the Power Supply Design embrace three different design
steps:
•
The electrical design
•
The thermal design
•
Thermal PCB layout
6.3.1.
Electrical Design Guidelines
The electrical design of the power supply depends strongly on the power source from
which this power is drained. We will distinguish them into three categories:
•
+5V input (typically PC internal regulator output)
•
+12V input (typically automotive)
•
Battery
6.3.1.1.
+ 5V input Source Power Supply Design Guidelines
•
The desired output for the power supply is 3.8V, hence there's not a big
difference between the input source and the desired output and a linear
regulator can be used. A switching power supply will not be suited because of
the low drop out requirements.
•
When using a linear regulator, a proper heat sink shall be provided in order to
dissipate the power generated.
•
A Bypass low ESR capacitor of adequate capacity must be provided in order to
cut the current absorption peaks close to the GE866-QUAD, a 100
μ
F tantalum
capacitor is usually suited.
•
Make sure the low ESR capacitor on the power supply output (usually a tantalum
one) is rated at least 10V.
•
A protection diode should be inserted close to the power input, in order to save
the GE866-QUAD from power polarity inversion.
