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Renesas Electronics America - Knowledgebase

Is it effective to connect resistors in series as a countermeasure?

Latest Updated:02/01/2008


Is it effective to connect resistors in series to their pins to protect semiconductor devices from damage, as a countermeasure against surge and static electricity?


No. Application of an overvoltage cannot be avoided by using a dumping resistor, because it only limits the current. To drop the voltage, a ground capacitor must be connected between the resistor and pin. If a large-capacitance capacitor that can absorb surge and static electricity is connected, however, the waveform may attenuate and this must be taken into account. For a MOS device, a diode must be connected at the power supply side to prevent an inrush current that flows when the power is turned off.
Comparing with these circuits, placing a Zener diode as a surge absorber between the signal line and ground is simpler.

Related page:Surge Absorber Device (NSAD series)
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