BU21072MUV_16 Datasheet, PDF (31/40 Pages) Rohm – Capacitive Switch Controller ICs

BU21072MUV / BU21078MUV / BU21078FV
(10) Ground wiring pattern
If small-signal GND and large-current GND are provided, It will be recommended to separate the large-current
GND pattern from the small-signal GND pattern and establish a single ground at the reference point of the set
PCB so that resistance to the wiring pattern and voltage fluctuations due to a large current will cause no
fluctuations in voltages of the small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern
of external parts as well.
(11) External capacitor
In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a
degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc.
(12) Rush current
The IC with some power supplies has a capable of rush current due to procedure and delay at power-on. Pay
attention to the capacitance of the coupling capacitors and the wiring pattern width and routing of the power
supply and the GND lines.
Status of this document
The Japanese version of this document is formal specification. A customer may use this translation version only for a
reference to help reading the formal version.
If there are any differences in translation version of this document formal version takes priority.
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14.Jul.2016 Rev.004