BU4051BC_15 Datasheet, PDF (12/21 Pages) Rohm – 8ch Analog Multiplexer/Demultiplexer

BU4051BC BU4051BCF BU4051BCFV
Operational Notes – continued
11. Unused Input Pins
Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and
extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small
charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and
cause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the
power supply or ground line.
12. Regarding the Input Pin of the IC
In the construction of this IC, P-N junctions are inevitably formed creating parasitic diodes or transistors. The
operation of these parasitic elements can result in mutual interference among circuits, operational faults, or physical
damage. Therefore, conditions which cause these parasitic elements to operate, such as applying a voltage to an
input pin lower than the ground voltage should be avoided. Furthermore, do not apply a voltage to the input pins
when no power supply voltage is applied to the IC. Even if the power supply voltage is applied, make sure that the
input pins have voltages within the values specified in the electrical characteristics of this IC.
13. Ceramic Capacitor
When using a ceramic capacitor, determine the dielectric constant considering the change of capacitance with
temperature and the decrease in nominal capacitance due to DC bias and others.
14. Area of Safe Operation (ASO)
Operate the IC such that the output voltage, output current, and power dissipation are all within the Area of Safe
Operation (ASO).
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TSZ22111 • 15 • 001
12/17
TSZ02201-0RDR0GZ00280-1-2
06.Jan.2015 Rev.001