LMH1228: Read timing of ADDR[1:0] at power up

Hirokazu Takahashi

Expert 8420 points

Part Number: LMH1228

Hello Support team,

I could find below description regarding SMBus address pins.

Could you let me know the timing definition to read ADDR[1:0] at power up process?

If you can show the timing chart with voltage level of VIN, it is helpful to understand it.

Best Regards,

Hirokazu Takahashi

over 3 years ago

0 Michael Lu (Santa Clara) over 3 years ago

TI__Mastermind 29655 points

Hi Takahashi-san,

The LMH1228 reads ADDR[1:0] once the device completes the POR cycle, after which the device is addressable via I2C.

Per datasheet (Section 6.6), T_POR = 50ms (max).

Thanks,

Michael

0 Hirokazu Takahashi over 3 years ago in reply to Michael Lu (Santa Clara)

TI__Expert 8420 points

Hello Michael-san

Thanks for your reply.

TPOR is defined as below in datasheet.

Is VDDIO same as VIN? LMH1228 doesn't have "VDDIO" pin.

Is Min of VDDIO 2.375V?

Best Regards,

Hirokazu Takahashi

0 Michael Lu (Santa Clara) over 3 years ago in reply to Hirokazu Takahashi

TI__Mastermind 29655 points

Hi Takahashi-san,

Yes, you are right, Min in this case is VDD_min, which is 2.375V.

Michael

0 Hirokazu Takahashi over 3 years ago in reply to Michael Lu (Santa Clara)

TI__Expert 8420 points

Hello Michael-san

Could you please let me know about below min value?

Best Regards,

Hirokazu Takahashi

0 Michael Lu (Santa Clara) over 3 years ago in reply to Hirokazu Takahashi

TI__Mastermind 29655 points

Hi Takahashi-san,

We do not have a specified measured min value for when SMBus address is set per your drawing. I have consulted with our design team, and we expect that the address should be set within 30ms. This is an estimate only.

Michael

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LMH1228: Read timing of ADDR[1:0] at power up