Hi Marcus, Right -- the output of the Octoclock is 5V. I'm not seeing how the N320 can accept that as an input. The knowledge base article says the N320 expects 5Vpp at the 1pps input. But the schematics/parts data sheet for the input buffer don't seem to support that . . . unless I'm missing something.
Thanks, Jim ________________________________ From: Marcus D. Leech <patchvonbr...@gmail.com> Sent: Friday, June 11, 2021 9:39 AM To: usrp-users@lists.ettus.com <usrp-users@lists.ettus.com> Subject: [USRP-users] Re: N320 1PPS input voltage On 06/11/2021 09:11 AM, Marcus Müller wrote: > Hello Jim, > > > hm, that knowledge base article must be wrong: The octoclock internally only > has a 3.3V > supply. But before I say something wrong here, let me check back. > > > Best regards, > > Marcus The 1PPS outputs on the Octoclock are bufered by 7404 inverters, which appear to have a 5V Vcc. > > > On 11.06.21 14:17, Jim Palladino wrote: > >> Hello, >> >> We are planning on using an octoclock with several devices, including an >> N320. The >> octoclock outputs a 5V 1pps signal, but I'm confused about the N320 1pps >> input. >> >> According to >> (https://urldefense.proofpoint.com/v2/url?u=https-3A__kb.ettus.com_N320_N321-29-3A&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=TdFHQJNItGehIsL1D4yXezIfq_vO05AvF1_lMSyNpHs&e= >> "PPS - Pulse Per Second Using a PPS signal for timestamp synchronization >> requires a >> square wave signal with the following a 5Vpp amplitude." >> >> If I look at the schematics for the N320, on page 15, >> (https://urldefense.proofpoint.com/v2/url?u=https-3A__kb.ettus.com_images_f_f4_USRP-5FN3XX-5FMB-5FSchematic.pdf&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=6JTHdP9IoYFRQhn24LgJjEofkuFwgAsHTs9iHhgMuBg&e=) >> they show that the input >> 1pps signal goes through an NC7SV157. Vcc for that is 3.3V in the schematics. >> >> According to the datasheet, the absolute maximum rating on the input is 4.3V. >> "https://urldefense.proofpoint.com/v2/url?u=https-3A__www.onsemi.com_pdf_datasheet_nc7sv157-2Dd.pdf&d=DwIF-g&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=XUEEtUEfpaAEGxRI-WGuqHauOvsPdD2NZkfwDnwpYx0&m=-9vS_HYCWF4BKKIX7QR3SO2LJ3yD1MyEElYsX5a8WMs&s=XPmiCDRDfM2wVtI1g4KChC9dkOJhMyrqBTMv_Rx01Xg&e="; >> >> So, I'm not sure how the N320 can safely accept a 5V input (from the >> octoclock or other >> device). >> >> Thanks, >> Jim >> >> >> _______________________________________________ >> USRP-users mailing list -- usrp-users@lists.ettus.com >> To unsubscribe send an email to usrp-users-le...@lists.ettus.com > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com _______________________________________________ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
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