LMC6482: Impedance Anomaly

anson zhou

Part Number: LMC6482

Tool/software:

Hi Sir :

The previous chip had a forward measurement of 669 for pin 3/4 and a reverse measurement of 1750 for pin 3/4;
New product chip 3/4 pin forward measurement 1531, reverse measurement 3/4 pin infinity;
The impedance value of the new version chip is about twice as high as before.

The internal structure of the chip has also undergone changes. Are these normal phenomena and will they affect normal use ？

3 months ago

0 Clemens Ladisch 3 months ago

Guru 316920 points

PCN 20180307000
PCN 20240401002.0.A
PCN 20240930007.1
PCN 20240930009.1

0 Alex Curtis 3 months ago

TI__Intellectual 2660 points

Hi Anson,

Firstly, pin-to-pin impedance measurements have limited value, as they aren't a measurement of the actual amplifier's performance.

The new op-amp is functionally equivalent to the old one. Although there may be some slight differences due to the fabrication (FAB) change, they should perform nearly identically in your application.

As part of the process change, modifications were made to the die to replicate the performance of the previous die in the new FAB. While these die changes may affect the results of pin-to-pin impedance measurements, they should not impact the overall performance of the part.

Best Regards,

Alex Curtis

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LMC6482: Impedance Anomaly