TPS6521815: Powering Cyclone V with DDR3 memory using TPS6521815 PMIC

Mohamed Yashar

Part Number: TPS6521815
Other Parts Discussed in Thread: TPS65218D0, TPS51206, TPS65218, TPS51200

Hello,

Hope you are doing well,

We are using TPS6521815 PMIC for powering Cyclone V GX with DDR3 memory, having few queries with sequencing and configuration part which I mentioned below,

So, in our system for the PMIC we are planning to use 3.3V rail as input. With this input we are expecting to get (1.1V from DCDC1 & DCDC2), (2.5V from DCDC3), (3.3V from DCDC4), (1.5V for DDR3 from LDO1) and VTT, VRef for DDR3. Sequence order as follows DCDC1 & DCDC2 -> DCDC3 & DCDC4 & LDO1 -> VTT & Vref

1. Whether this part has an EVAL board or reference design for cyclone V with DDR3? If yes kindly share its link. also, I found one reference design for Cyclone V with TPS65218D0, but schematic sheet no.3 is missing in that document tidrge2.pdf for your reference.

2. How can I configure and sequence to get the expected output which i have mentioned above?

3. Which pin should be used for Vtt and Vref ?

Expecting your response as soon as possible.

Regards,

Yashar

6 months ago

0 Matt Sunna 6 months ago

TI__Guru* 78863 points

Hi Yashar,

I assume this is the reference design you have seen? https://www.ti.com/tool/TIDA-00606

The video on this page goes through some example configurations which should be helpful to program the settings and sequencing.

For DDR termination, I think some reference designs use the TPS51206 - this thread may be a helpful starting point: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/970864/tps65218d0-ddr3-dynamic-on-die-termination

I will assign this thread to an expert for the TPS65218 in case you have further questions.

Best regards,

Matt

0 Mohamed Yashar 6 months ago in reply to Matt Sunna

Prodigy 40 points

Sure please do assign.

0 James Steenbock 6 months ago in reply to Mohamed Yashar

TI__Mastermind 18290 points

Hi Mohamed,

If you have questions after checking the reference design let us know.

Regards,

James

0 Mohamed Yashar 6 months ago in reply to James Steenbock

Prodigy 40 points

Hi James,

I have gone through the reference design document www.ti.com/.../TIDA-00606 , but schematic sheet no.3/3 is missing in that document. also, I need to know from which pin I should take VTT and Vref for DDR3?

Regards,

Yashar

0 James Steenbock 6 months ago in reply to Mohamed Yashar

TI__Mastermind 18290 points

Hi Mohamed,

VTT and VREF need to come from a DDR termination regulator like TPS51200 that has sink and source current capability. Do you already have a device like this and you are asking how to supply the VIN or LDOIN on that termination regulator?

You can't supply VTT on the DDR memory with one of the rails from TPS6521815 because they don't have the accurate sink and source capability. For DDR it is important that the loop response be fast so that the regulator can respond to changing DDR load conditions without causing data errors on the VTT line.

Regards,

James

0 Mohamed Yashar 6 months ago in reply to James Steenbock

Prodigy 40 points

Okay I got your point, so I have to use another regulator TPS51200 for Vref, Vtt also in that pin like VLDOIN, REFIN, VIN whose input should be given from PMIC TPS65218. am I right?

Thanks,

Yashar

0 Mohamed Yashar 6 months ago in reply to James Steenbock

Prodigy 40 points

Yes, how to supply VIN, VLDOIN on that termination regulator with TPS65218? and which pin should be used?

0 James Steenbock 6 months ago in reply to Mohamed Yashar

TI__Mastermind 18290 points

Hi Mohamed,

Any of the BUCKs would be a good option for VLDOIN so that you can support the DDR current requirements.

For the generic VIN of the DDR termination regulator, you might need a different voltage than VLDOIN, but I believe VIN will need less current than VLDOIN since VIN doesn't connect to the main load current.

There's no specific pin recommendation. The main thing you need to do is make sure that your supplies to the DDR termination regulator inputs can meet the voltage and current requirements. Since you are using the programmable TPS6521815, these supplies could come from any capable BUCK and be sequenced in a custom order as necessary.

Regards,

James

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TPS6521815: Powering Cyclone V with DDR3 memory using TPS6521815 PMIC