AM3352: PMIC selection

Kummi

Part Number: AM3352
Other Parts Discussed in Thread: TPS650250

Hi,

We have a new project on AM3352 (1GHz) and we need advice in selecting right PMIC.
As the input voltage is 3.6V to 6.0V, only PMIC option we have is TPS650250..

But the power solution in the wiki page mentions TPS650250 supports only OPP50/OPP100.
Is there any reason why TPS650250 cannot be used for Turbo and Nitro?
processors.wiki.ti.com/.../AM335x_Hardware_Design_Guide

As per the AM335x datasheet current consumption for Nitro is 1000mA (MAX).

Whereas TPS650250's DCDC1 can supply upto 1600mA(MAX).

And this application even though runs at 1GHz it uses only minimal peripherals,
so we wonder if we could use TPS650250 for Turbo and Nitro?

Best Regards
Kummi

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

The reason for this comment on the wiki page is that the AM335X ROM code initializes the MPU at 500MHz, which is a frequency in the OPP100 range, requiring 1.1V on the VDD_MPU rail. After that TPS650250 has no means of software control of the SMPS output voltage, in order to raise it to the levels required for higher OPP operation.

However it's allowed to boot the AM335x with VDD_MPU directly se to Nitro levels. See this post: e2e.ti.com/.../1936978

0 Biser Gatchev-XID over 8 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

One other thing that you need to consider though, is the fact that you cannot use the same SMPS for both VDD_CORE and VDD_MPU in this case. You will need separate power supplies for them, as VDD_CORE must operate at 1.1V.

0 Kummi over 8 years ago in reply to Biser Gatchev-XID

Mastermind 6220 points

Hi Biser,

Thank you very much for the quick information.

So can we assume that we can use TPS650250 + additional IC for VDD_CORE(1.1V)
to support Nitro in AM335x?

Please let me know if there is any other one chip solution that support Nitro
and with Input voltage up to 6.0V

PMIC input voltage: 3.0V to 6.0V
Operating Temperature: -40 deg to 105 deg

Best Regards
Kummi

0 Biser Gatchev-XID over 8 years ago in reply to Kummi

TI__Guru**** 393215 points

Yes, you will need a 1.1V power source. No, I'm not aware of any other AM335x PMICs with 6V input.

0 Kummi over 8 years ago in reply to Biser Gatchev-XID

Mastermind 6220 points

Hi Biser,

Thank you for the information.

As per the above discussion we are trying to design power supply
with TPS650250 + External DC/DC for VDD_CORE(1.1V) in order to support
AM3352 1GHz(Nitro) operation. Also planning to use DDR3L.
Please let me know if the below connection with External DC/DC is a possible option
and if there is anything else to be careful about.

The above connection is as per the Table 3(TPS650250 to Support DDR3) from SLVU731A.

Best Regards
Kummi

0 Biser Gatchev-XID over 8 years ago in reply to Kummi

TI__Guru**** 393215 points

You must be careful not to overload the two 1.8v LDO's. Each of them has a max. output current of 200mA. Otherwise this looks OK to me.

0 Kummi over 8 years ago in reply to Biser Gatchev-XID

Mastermind 6220 points

Hi Biser,

We need one clarification on using TPS650250 to operate AM335x at 1GHz(nitro).
As per the above discussion we could use TPS650250 + External DC/DC for VDD_CORE(1.1V).

Will it be OK to use External DC/DC to power VDD_MPU(1.35V) instead of VDD_CORE?

Best Regards
Kummi

0 Biser Gatchev-XID over 8 years ago in reply to Kummi

TI__Guru**** 393215 points

Yes of course, as long as the load current and power sequencing requirements are met.

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AM3352: PMIC selection