ONET1141L: Register Question

Mihir Gupta65

Part Number: ONET1141L

Team,

I have a customer that is working with the ONET1141L. They have a question a about the register 1, bit 4: "High Modulation Current enable bit".

What does this mean exactly? What is the effect to register 2,3 where the modulation current is set?

The customer will use the part in a 35Ohm transmission line at the output of the ONET1141L and wants to have here a 2Vpk-pk amplitude by increasing the modulation current. How would they do this in the registers?

Thanks and Regards,

Mihir Gupta

FAE - South Germany

over 6 years ago

0 Sriharsha Kota Pavan over 6 years ago

TI__Intellectual 1715 points

Hi Mihir,

I'm looking into this with our team- will get back to you very soon.

Thanks for bearing with us.

Regards,

Sri

0 Mihir Gupta65 over 6 years ago in reply to Sriharsha Kota Pavan

TI__Intellectual 2155 points

Hi Sri,

Do you have an update for me?

Thanks and regards,

Mihir

0 Sriharsha Kota Pavan over 6 years ago in reply to Mihir Gupta65

TI__Intellectual 1715 points

Hi Mihir,

Yes, I just heard back from our team on this:

The "high modulation current enable" (HCENA) bit increases the bias current for the ModCurrent DACs by 25%, which means that the modulation o/p voltage (MAX) as well as the step size increases correspondingly for the same register settings of Reg 2 & 3.

If the customer wants to achieve 2Vpp SE with, we recommend them to set the HCENA = 1 and use a register setting of MODC = (800)10 or (810)10 according to the Fig. 14 in the Datasheet of ONET1141L.

Hope this helps, please feel free to ask any further questions.

Thanks,

Sri

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ONET1141L: Register Question