LM98620: Recovery time from power-down mode

Prodigy 130 points

Part Number: LM98620

Hi,

I found two power down mode on the data sheet, page 8.

1. MCLK Active
Is this mode activated by Reg-0x00 bit[4]=1 ?

2.MCLK Stopped
This mode is caused by stopping external MCLK

my question is,

Is the above my understanding correct?

Tell me how much second to come back from each power-down mode.

regards,

over 3 years ago

0 Shinya Morita over 3 years ago

TI__Mastermind 30205 points

Hi,

Let me investigate your questions and feedback to you by Dec 11th.

regards

Shinya

0 Shinya Morita over 3 years ago in reply to Shinya Morita

TI__Mastermind 30205 points

Hi,

1 MCLK ACTIVE is mode is under condition of Reg 0x00 bit4 =1 and MCLK active.

2 is Reg 0x00 bit 4 = 1 and no MCLK input.

LM98620 could recover less than 1 second.

regards

Shinya

0 az over 3 years ago in reply to Shinya Morita

Prodigy 130 points

Hi Shinya,

Thank you for your kind support.

I tried "MCLK Active" power-down in my system with ~1 sec. recovery wait time. But output images were not clear and the ADC output seemed to be unstable.

I cannot use longer wait time because of our product spec.

I checked that VREFTOUT and VREFBOUT voltage were recovered within 300us. It looked OK for ~1sec recovery time.

Which pin rises the slowest? How can I find the device is ready? And tell me how to calculate the enough wait time.

regards,

0 Shinya Morita over 3 years ago in reply to az

TI__Mastermind 30205 points

Hi,

Thank you for your questions. Let me investigate them and feedback to you by Dec 18th.

regards

Shinya

0 Shinya Morita over 3 years ago in reply to Shinya Morita

TI__Mastermind 30205 points

Hi,

Slowest pin I expect is VCLPEXT since it has largest cap. I think 1 sec is much enough long to wait. We may have other reason for instability.

Another idea to try is software reset. Add 0x06. "0" reset state machine of LM98620."1" is state machine + register settings. It may help making stable after backing from power down mode.

regards

Shinya Morita

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LM98620: Recovery time from power-down mode