iMX7D based design and some questions

[mubinicyer]

Hi,

We want to design a board based on iMX7D for a mobile application (tablet). We are investigating the schematic of SABRE board and have some questions:

1. According to block diagram of SABRE board, there are 11 voltage sources. The total power: 

                  SW1A=1.1Vx1A=1.1W,

                  SW1B=1.0Vx1.75A=1.75W,

                  SW2=1.8Vx1.25A=2.25W,

                  SW3=1.35Vx1.25A=1.69W,

                  LDO1=1.8Vx0.1A=0.18W,

                  LDO2=1.5Vx0.25A=0.375W,

                  LDO3=3.3Vx0.1A=0.33W,

                  LDO4=2.8Vx0.35A=0.98W,

                  VSD=1.8Vx0.1A=0.18W

                  V33=3.3Vx0.35A=1,155W

Totaly ~10 watt of power! How can it be possible with a LiIon or LiPol battery? Which  powers can we "avoid" for a battery application? If we could neglect (or avoid) some power schemes, which PMIC (with battery charging functionality) could you recommend?

      2. Which SDRAM should we use, DDR3L or LPDDR3. I think LPDDR3 is suitable for package-on-package designs. Is there any other advantages of LPDDR3 over DDR3L?

Thanks.

[gusarambula]

Hello Mubin Icyer,

The values show on the SABRE schematic indicate the capabilities of the supplies, not the power consumed. I would recommend looking at Application Note 5383 (link below) which show a couple of use cases and have some recommendations for lowering power consumption which is indeed critical when running from batteries.

https://www.nxp.com/docs/en/application-note/AN5383.pdf

There are also some benchmarks that show extreme use cases which most likely do not reflect real life applications but allow to see the absolute maximum amount of power that may be required.

As for the SDRAM, the i.MX7D supports both DDR3L and LPDDR3. However, there is not a PoP (Package-on-package) version of the i.MX7D. Both have advantages and disadvantages when it comes to price and power consumption so it would depend on your design.

I hope this helps!

Regards,