MAX3222, MAX3221, SN65C3221 - Acceptable RIN voltage at VCC=0V

Kawai

Guru 19785 points

Other Parts Discussed in Thread: MAX3221, MAX3222, SN65C3221

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

over 9 years ago

0 Clemens Ladisch over 9 years ago

Guru 322000 points

If the recommended operation conditions for V_I were dependent on the V_CC level, they would mention "V_CC" 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 V_CC = 0.

0 Ron Michallick over 9 years ago

TI__Guru**** 170856 points

Kawai-san,

Yes they are input tolerant at VCC = 0V

Current only flows to ground.

0 Kawai over 9 years ago in reply to Ron Michallick

Guru 19785 points

Hi Ron-san, Clemens-san,

Thanks for your support.

Best Regards,
Kawai

0 Kawai over 9 years ago in reply to Ron Michallick

Guru 19785 points

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

0 Ron Michallick over 9 years ago in reply to Kawai

TI__Guru**** 170856 points

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.

0 Kawai over 9 years ago in reply to Ron Michallick

Guru 19785 points

Hi Ron-san,

Thank you for the information.

Best Regards,
Takushi

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MAX3222, MAX3221, SN65C3221 - Acceptable RIN voltage at VCC=0V