Hi Team,
I believe these RS-232 devices (MAX3222, MAX3221, SN65C3221) are input tolerant, voltage input acceptable to RIN pins when VCC=0V. At this condition, can we say there is no leak voltage or current to VCC ?
Best Regards,
Kawai
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If the recommended operation conditions for VI were dependent on the VCC level, they would mention "VCC" somewhere.
There always is a (small) leakage current. The datasheet explicitly says "over recommended ranges of supply voltage", so there are no guarantees how large the leakge might be for VCC = 0.
Kawai-san,
Yes they are input tolerant at VCC = 0V
Current only flows to ground.
Ron-san,
I have one more question to this.
RIN is input tolerant at VCC=0V, so can we say RIN input signal lower than absolute maximum rating would not damage the device or lead to abnormal operation ?
* Customer sees 200mV leak voltage at VCC pin when RIN applied at no VCC supply.
Best Regards,
Kawai
Takushi-san,
Yes, no damage and no abnormal operation.
How was the voltage on VCC measured? VCC pin in circuit or out.
What is the impedance of meter?
Try short VCC to ground with an current meter and measure any leakage current.