LMX2615-SP: applying signals during powered-off

Noriyuki Takahashi

Part Number: LMX2615-SP

Hi team,

Cusomter wants to understand whether it's OK to apply singals during LMX2615-SP powered-off.

Looking at the absolute maximum ratings, Digital pin voltage (FS0-FS7, SYNC, SysRefReq, RECAL_EN, CAL) needs to be less than +0.3V during LMX2615-SP powered-off. And Differential AC voltage between OSCinP and OSCinN needs to be less than 2.1Vpp. Is this right?

Regards,

Noriyuki Takahashi

over 3 years ago

0 Noel Fung over 3 years ago

TI__Guru** 107110 points

Hi Takahashi-san,

As long as the input signals are within the max. rating, it should be fine. For example, the signals apply to SPI interface should not be higher than Vcc when LMX2615 is off.

0 Noriyuki Takahashi over 3 years ago in reply to Noel Fung

TI__Genius 10980 points

Noel,

Could you confirm whether my understanding as below is correct?

The abs max of VDIG is (VCC+0.3)V. So when the VCC is 0V, that is, LMX2615-SP is powered-off, the abs max of VDIG is 0.3V.

Regards,

Noriyuki Takahashi

0 Noel Fung over 3 years ago in reply to Noriyuki Takahashi

TI__Guru** 107110 points

Hi Takahashi-san,

When Vcc = 3.3V, VDIG cannot be higher than 3.6V.

When Vcc = 0V, we don't know what is the max. VDIG as this is not a valid operating mode, we did not characterize this use case. From the design point of view, the risk is low as long as VDIG is below 3.6V.

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LMX2615-SP: applying signals during powered-off