TPS51200 VTT supply

Shareef

Expert 1985 points

Other Parts Discussed in Thread: TPS51200, TPS51206

Hi All,

I am using the TPS51200 device to generate 0.75V termination supply for my DDR3 circuit. On my board, there are four DDR3 controllers and all the 4 controllers are sourced VTT supply from a single TPS51200 VTT regulator. As per the calculation, the overall current source/sink requirement on VTT for all the 4 DDR3 controllers is around 1.8A. Do you forese any issues?

Regards,

Khader Shareef

over 14 years ago

0 Nancy Zhang over 14 years ago

TI__Mastermind 49470 points

Hi Khader,

There is no issue for this application. The TPS51200 ensures the VTT output voltage to be VTTREF-25mV<VTT<VTTREF+25mV for both DC and AC conditions at -2A<Ivtt<2A. The VTT output voltage is measured at controller VTT pin side.

Thanks,

Nancy

0 Titusc over 13 years ago

Intellectual 660 points

Hi all,

I am planning to use TPS51206 to generate .75V termination supply for two sets of DDR3 chips on my board. Each set belongs to a different IC. I notice the TPS51206 has a 2A limit. How do I calculate the maximum current my DDR3 chips will draw?

Thanks,
Titus

0 Titusc over 13 years ago in reply to Titusc

Intellectual 660 points

I think I know the answer to my own question now.

VTT/term_res = .75/50R = 15mA.

15mA * number of terminating resistors (26 + 25 + 25) ~= 1.2A.

Since this is below the 2A limit, I guess I am ok?

0 Nancy Zhang over 13 years ago in reply to Titusc

TI__Mastermind 49470 points

Hi Titusc,

Yes, you are right. TPS51206 fits your application.

Thanks,

Nancy

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TPS51200 VTT supply