DS90LV001: both input 100ohm termination and output terminate are needed for DS90LV001, is it right? Comparing with DS10BR150

Ken Zhang

Part Number: DS90LV001
Other Parts Discussed in Thread: DS10BR150

hi,

In DS10BR150， both 100Ω Input termination and 100 Output Termination are integrated。 but for DS90LV001, there is no any in-chip termination.

Is it means that both external 100 input termination and 100 output termination must be added in design for 500MHZ LVDS signal?

over 3 years ago

0 David (ASIC) Liu over 3 years ago

TI__Guru**** 171116 points

Hi,

A termination resistor is required only on the input. It should match the characteristic impedance of the transmission line (90Ω to 110Ω).

Thanks

David

0 Ken Zhang over 3 years ago in reply to David (ASIC) Liu

TI__Expert 3315 points

David;

why is a 100 output termination integrated in DS10BR150, but 100 ohm output termination is not needed in DS90LV001?

0 David (ASIC) Liu over 3 years ago in reply to Ken Zhang

TI__Guru**** 171116 points

Hi,

The output resistor on this part helps to match the output impedance with the transmission line impedance. This is necessary for good transmission characteristics.

Thanks

David

0 Ken Zhang over 3 years ago in reply to David (ASIC) Liu

TI__Expert 3315 points

I am confused with below message. does below comments mean that adding 100ohm output termination on DS90LV001 is preferred?

The output resistor on this part helps to match the output impedance with the transmission line impedance. This is necessary for good transmission characteristics.

0 David (ASIC) Liu over 3 years ago in reply to Ken Zhang

TI__Guru**** 171116 points

Hi,

Internal 100-ohm resistor provides back termination. This back termination, with the100-ohm termination at the receiver, and the controlled trace impedance, provide optimum signal conditioning from signal integrity point of view. Otherwise there could be reflection - due to impedance mis-match.

On the other hand, a normal buffer, such as the DS90LV001 would operate at a much lower data rate and thus meeting tight impedance controlled environment is not a concern as much, so you do not need 100ohm termination at its output.

Thanks

David

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DS90LV001: both input 100ohm termination and output terminate are needed for DS90LV001, is it right? Comparing with DS10BR150