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Re: [802.3_4PPOE] Diode mismatch values



Hi Jeff, all,

The diode data were provided by me.

They come from production data, so they consider the spread among different lots of production.

I also derived the linearized model, which is not coming from a measurement, but the linearization of the worst case operating points at 0.5A

This is the relevant slide of beia_1_0514.pdf.

Please let me know if you have any question

Best regards

Christian

 

 

 

 

From: Jeff Heath [mailto:jheath@xxxxxxxxxx]
Sent: Wednesday, July 02, 2014 1:05 AM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Diode mismatch values

 

Sorry for my typo.  My lab data showed only a 0.030V Vt mismatch, not a 0.30V mismatch…

 

Regards,

 

Jeff Heath
Design Center Manager

Description: Linear Technology Corporation

 

 

paper:

402 East Carrillo Street, Suite D

 

Santa Barbara, California 93101

voice:

805.965.6400

fax:

805.965.1701

computer:

jheath@xxxxxxxxxx

 

www.linear.com

 

 

From: Jeff Heath [mailto:jheath@xxxxxxxxxx]
Sent: Tuesday, July 01, 2014 4:00 PM
To: 'STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx'
Subject: Diode mismatch values

 

Yair,

 

The diode mismatch parameters I your presentation show a wide variation of threshold (.39V vs .53V) and a zero difference in resistance (0.25 ohms vs 0.25 ohms). 

 

I have included my previous lab data on just six diodes which shows just the opposite: a threshold that is very close (Varying by only 0.30V) and a resistance that is wide (0.28 ohms vs 0.40 ohms).

 

Given that in the short channel case, the threshold offset is the major contributor to offset currents, I think we should change the values for the diode mismatch.

 

Regards,

 

Jeff Heath
Design Center Manager

Description: Linear Technology Corporation

 

 

paper:

402 East Carrillo Street, Suite D

 

Santa Barbara, California 93101

voice:

805.965.6400

fax:

805.965.1701

computer:

jheath@xxxxxxxxxx

 

www.linear.com