Installation and Operation
2018 Microchip Technology Inc.
DS50002815A-page 14
2.3.1.9
PCB LAYOUT CONSIDERATIONS
For the best performance with the minimum occupied board space, some proper layout
techniques should be applied. First, the input and output capacitors should be placed
as close to the MIC23656 as possible and on the same layer as the IC. This will ensure
low ripple and lower switching noise. Then, vias must be used under the MIC23656,
from its exposed pad to the GND plane, in order to improve heat dissipation. Lastly, the
switching node (from the SW pin of the MIC23656 to the inductor) should be as small
as possible to decrease EMI emission.
2.3.1.10 BENCH TESTING AT HIGH CURRENTS
When testing the MIC23656 device at high-load currents or when checking the over-
current protection behavior, it may be necessary to remove the series ammeter shown
in
or to replace it with a very low-value shunt resistor. This is because the
internal resistance of many Digital Multimeters (DMMs) used for current measurements
is generally too high.
2.3.1.11
THERMAL CONSIDERATIONS
The MIC23656 Junction-to-Ambient Thermal Resistance
JA, as measured on the
Evaluation Board, is approxi45°C/W. Depending on the loading conditions,
ambient temperature, and device settings, the junction temperature might exceed the
rated operating limit of +125°C due to internal power dissipation. Continuous operation
above the maximum operating limits stated in the data sheet should be avoided.
