Perhaps one of you chip gurus could shed some light on why Infineon would use such a large package with so many NC pins on their SLB9645. VQFN-32 with 21 NC pins and a TSSOP-28 with 17 NC. < https://www.infineon.com/cms/en/product/security-smart-card-solutions/optiga-embedded-security-solutions/optiga-tpm/slb-9645xq1.2/ > Just wondering if it's related to the die size or something like that -- Chisolm Republic of Texas
Chip with large number of NC pins
Started by ●March 20, 2018
Reply by ●March 20, 20182018-03-20
On 03/20/2018 12:04 PM, Joe Chisolm wrote:> Perhaps one of you chip gurus could shed some light on why Infineon would > use such a large package with so many NC pins on their SLB9645. > VQFN-32 with 21 NC pins and a TSSOP-28 with 17 NC. > > < https://www.infineon.com/cms/en/product/security-smart-card-solutions/optiga-embedded-security-solutions/optiga-tpm/slb-9645xq1.2/ > > > Just wondering if it's related to the die size or something like that >Usually die size or thermal conduction, AFAIK. At the top of P.10 of the datasheet, it says that the NC pins "must not be connected externally (must be left floating)"--they're "do not connect" rather than "unconnected", so I imagine it's for test and programming in this case. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
Reply by ●March 20, 20182018-03-20
On Tue, 20 Mar 2018 12:18:36 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 03/20/2018 12:04 PM, Joe Chisolm wrote: >> Perhaps one of you chip gurus could shed some light on why Infineon would >> use such a large package with so many NC pins on their SLB9645. >> VQFN-32 with 21 NC pins and a TSSOP-28 with 17 NC. >> >> < https://www.infineon.com/cms/en/product/security-smart-card-solutions/optiga-embedded-security-solutions/optiga-tpm/slb-9645xq1.2/ > >> >> Just wondering if it's related to the die size or something like that >> > >Usually die size or thermal conduction, AFAIK. At the top of P.10 of >the datasheet, it says that the NC pins "must not be connected >externally (must be left floating)"--they're "do not connect" rather >than "unconnected", so I imagine it's for test and programming in this case.Or it's another, more general part, programmed for a specific purpose. Those pins do something but not needed for this application.