DS25BR440: LVDS interface

Yanjie Liu-Kost

Prodigy 10 points

Part Number: DS25BR440

Tool/software:

HI,

Can I connect a LVDS interfac with SPEC:

VOH min.1.1V,

VOL Max.0.745V,

VOD_AC(transmitter differential output voltage) 390-800mV

VOD_DC (DC range for the VOD): Min.400mV

VCM (transmitter common mode voltage): 775mV- 1025mV

I could not understand the SPEC in 'LVCMOS DC SPECIFICATIONS ' and 'LVDS INPUT DC SPECIFICATIONS' table. the voltages in those two sections for me are contradictory.

Hope somebody could help me

Kindly regards,

Yanjie

1 month ago

0 Brian Zhou 1 month ago

TI__Guru*** 145435 points

Hi Yanjie:

DS25BR440 input can receive LVDS output signal

this is for single ended signal. IN+ or IN-

This is for differential input signal IN+ - IN-

Best

Brian

0 Yanjie Liu-Kost 1 month ago in reply to Brian Zhou

Prodigy 10 points

Hi Brain,

thanks for the replay, it is clear of TI SPEC now. Pity the interface SPEC I am checking does not really separate the DC and AC SPEC, it is a LVDS interface. But SPEC is like:
VOD_AC (transmitter differential output voltage): 390~800mV

VOD_DC : range for the VOD (Transmitter differential output voltage): Min. 400mV

VCM: transmitter common mode voltage: 775-1025mv

Can I understand my VCM is your DC low level voltage? If yes, it almost match. But other numbers I don't know how to map them to your SPEC.

Kindly regards,

Yanjie

0 Brian Zhou 1 month ago in reply to Yanjie Liu-Kost

TI__Guru*** 145435 points

Vcm is average of high voltage and low voltage.

If Vh is 2v and Vl is 1v, Vcm is 1.5v.

Best

Brian

0 Yanjie Liu-Kost 1 month ago in reply to Brian Zhou

Prodigy 10 points

So my interface Vcm is Min.0.7V ~ Max.1V, seems not 100% match the DS25BR440 data sheet. Can I still give a try?

Kindly regards,

Yanjie

0 Brian Zhou 1 month ago in reply to Yanjie Liu-Kost

TI__Guru*** 145435 points

HI Yanjie:

LVDS common mode voltage is 1.2v, DS25BR440 should support .

Best

Brian

0 Yanjie Liu-Kost 1 month ago in reply to Brian Zhou

Prodigy 10 points

Thank you Brain, I will build a test PCB to try out.

Kindly regards,

Yanjie

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DS25BR440: LVDS interface