LMH1208: LMH1208: No output on 12G-SDI (sdi_out1± and sdi_out2± Neither output）

user4123229

Prodigy 30 points

Part Number: LMH1208
Other Parts Discussed in Thread: LMH1219, LMH1228, LMH0397, LMH1297

Our design is lmh1219 + lmh1208, which requires one 12g-sdi input and four 12g-sdi outputs
Now we have designed two versions, but none of them are correct. The version1.1，the LMH1208 sdi_out1± and sdi_out2± Neither output（12G-SDI）；The version1.2，the LMH1208 sdi_out1+and sdi_out2+ both output（12G-SDI），But SDI-OUT1- and SDI-OUT2- must connect GND (75R)，Fail to meet the requirements of 4 output signals。The version1.1 and version1.2 right for 6G-SDI,(ALL)
The SLEW_CYRL and VOD IO / registor is setting 12G rate. LOCK_N PIN and lock registor display ok ,I have read the register information.
Question : What are the LMH1208 requirements for industrial PCB ; S1000 ，TU872SLK(SP)，TU883(T2) ?
If the following PCB supports，What else should we pay attention to？

over 5 years ago

0 user4123229 over 5 years ago

Prodigy 30 points

0 Nasser Mohammadi over 5 years ago in reply to user4123229

TI__Guru* 93670 points

Greetings,

LMH1208, LMH1228, LMH0397, and LMH1297 are pin and register compatible. We use the same PCB for these devices. Please attached note board material used for these devices and LMH1219.

It would be a good idea to use LMH1228 instead of LMH1208 at first. Once perD TU-722 Hi-Tg 056 LMH1297 Board Material.pdfformance looks good, then you can replace LMH1228 with LMH1208 and fine tune settings as needed.

It is a good practice to terminate un-used-75-ohm outputs when these are not used. This would provide a balanced impedance on both positive and negative side of the output.

Regards,, Nasser

0 user4123229 over 5 years ago in reply to Nasser Mohammadi

Prodigy 30 points

0 Nasser Mohammadi over 5 years ago in reply to user4123229

TI__Guru* 93670 points

Greetings,

In the earlier email, i sent board material that we are using for 12G SDI evaluation boards. Please send me email and we can send you pcb layout to help with the pcb layout. Here is email: nasser.mohammadi@ti.com

Regards,, Nasser

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LMH1208: LMH1208: No output on 12G-SDI (sdi_out1± and sdi_out2± Neither output）