TP3420A Protection and Clocking Questions

Dan LaChance

Other Parts Discussed in Thread: TPD2E007, TPD2E001

Customer is using the TP3420A device. The TP3420A Line Interface Circuit Considerations Application Note (Section F on page 7) references two parts that are obsolete. TISP2180 from TI and P1553AA from Littlefuse. Customer looking at the P3100SCLRP from Littlefuse as replacement. Is there a better recommendation?

Customer is using the ISDN in TEM (TE Master) mode. If he picks format 1, can he still change the clock frequency? On the datasheet table 3 says it is fixed depending on the format he picks. On page 14 of the datasheet commands BCLK1n to BCLK4n allow him to change them. Which is correct?

over 12 years ago

0 LeonardEllis over 12 years ago

TI__Guru 71526 points

Hi Dan,

I did not find the App Note you referenced, but did find this one for the TP3402A: www.ti.com/lit/an/snoa821/snoa821.pdf . Page 6 Fig 2 shows a protection circuit that uses 1N4004, but I consider this a rather dated implementation. (Please send me the document number of the App Note you have so I can compare - never mind, I just found snoa823, and I see it references the old Triac, etc.)

The P1553AA is a TVS device, so I think the TPD2E007 might be a suitable replacement, but let me get with the ISDN Product Group and see if they have an updated recommended protection scheme: http://www.ti.com/product/tpd2e007 .

-Leonard

0 LeonardEllis over 12 years ago

TI__Guru 71526 points

Here's an App Note from Semtech on ISDN protection. In place of the LC03-6 in Fig 2, use the TPD2E007, and in place of the SR05 in Fig 3 use the TPD2E001.

http://www.ti.com/product/tpd2e001 ,

http://www.ti.com/product/tpd2e007 .

6136.ISDN_SurgeProtection.pdf

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TP3420A Protection and Clocking Questions