MAX3243E fail issue

Kai Hsiao

Guru 12675 points

Other Parts Discussed in Thread: MAX3243

Dear Sir

We use measure fail MAX3243 impedance ,we find pin9 and pin11 impedance is different between pass ic and fail ic

Pin9 and pin11 connect with pin3 ,is it workable or over SPEC ??

Please kindly help

over 9 years ago

0 Michael J Schultis over 9 years ago

TI__Mastermind 24995 points

Hello Kai,

Can you please describe what you mean by fail IC? In what way is it failing?
Why are pins 9 and 11 connected to V-?

Best,
Michael

0 Kai Hsiao over 9 years ago in reply to Michael J Schultis

Guru 12675 points

Dear Michael

1. This circuit is our end customer 's schematic
2. I never see this kindly of schematic to pull resister to V- ,but so far fail rate is 5% for total 20pcs set ,so I want to confirm the schematic is right or not
3. We remove this fail IC to another board ,but the fail issue is following the fail IC ,RS232 function can't workable

Could you kindly help to provide your suggestion?

Thanks

0 Michael J Schultis over 9 years ago in reply to Kai Hsiao

TI__Mastermind 24995 points

Kai,

The schematic is not right.
The V- pin should not have a resistor to the Dout pins. The V+ and V- pins are designed to have a capacitor on them only.

The device was likely permanently damaged which is why it does not work on another board.

I suggest removing those two resistors.

Best,
Michael

0 Ron Michallick over 9 years ago in reply to Michael J Schultis

TI__Guru**** 167546 points

Kai,

If the new board also has the resistor the device will still fail because the resistor may interfere with charge pump start up.
Try removing this resistor.

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MAX3243E fail issue