nandtest error

[Jeff Lauruhn (jlauruhn)]

Hello Richard 

That's a great question.  Mainly it has to do with ONFI, they define packages and pin outs and it's in our best interest to design to ONFI standards for interoperability.  ONFI is driven by NAND, Controller and End Customers, the original ONFI standard in 2007 defined 4 package types TSOP-48,  WSOP-48, LGA52 and BGA-63, since then only a few options have been requested and added BGA-100, BGA-132, BGA-152 (these last two are interchangeable) and BGA-272 and BGA-316 (.8mm) .  I believe TSOP is still the most used, and I think that may be for legacy reasons; once the board was laid out for TSOP our customers could quickly and continually double the memory by simply dropping in the next TSOP and tweaking the Firmware.  I'm not sure why no one is proposing smaller package sizes to ONFI at this time.  I suspect IoT may start driving smaller packages.  



Jeff Lauruhn
NAND Application Engineer
Embedded Business Unit
Micron Technology, Inc

-----Original Message-----
From: Ricard Wanderlof [mailto:ricard.wanderlof at axis.com] 
Sent: Monday, May 04, 2015 5:27 AM
To: Jeff Lauruhn (jlauruhn)
Cc: Linux mtd
Subject: RE: nandtest error


Hi Jeff,

A question that might be of interest for others on the list; myself I've always been curious of this fact: how come NAND flash chips traditionally come in TSOP packages where only 16 or so of the 48 pins are in fact used; why not use a smaller package?

My guess has been that the chip inside is so big that it requires a large package but I have no idea if this in fact is true or not.

/Ricard
-- 
Ricard Wolf Wanderlöf                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
Phone +46 46 272 2016                           Fax +46 46 13 61 30