LSF0102: Leakage from Bn to An

Charles (KAT) Zhang

Part Number: LSF0102

Tool/software:

Hi team,

My customer (Len~) want to know for LSF0102, if Bn port is ~0.7V @ LOW state, will this low voltage leaks to An port at low state?

From the D/S it seems Bn is connected directly to An if any of them are Low, (Bn will leak to An), but in Intel latest reference design they actually use this device to block the leakage. So want your confirm here.

Thank you,

Charles

11 months ago

0 Clemens Ladisch 11 months ago

Guru 316940 points

For voltages below Vref_A, the LSF indeed works as an analog switch.

The I/Os are isolated only when EN is pulled low. Is this what Intel's reference design is doing?

0 Jack Guan 11 months ago

TI__Mastermind 40656 points

Hi Charles,

Similar to the suggestion from Clemens', it is possible to use this device to separate signals from the I/Os from influencing one another,. It would require EN pin to be driven low through an-open drain driver, similar to the setup shown here: www.ti.com/.../5614304068001

Regards,

Jack

0 Charles (KAT) Zhang 11 months ago in reply to Jack Guan

TI__Intellectual 1595 points

Hi Jack, Clemens,

Thanks for the reply,

I didn't see Intel used the EN pins... Strange, thanks for the confirmation, let me check with the customer.

0 Jack Guan 11 months ago in reply to Charles (KAT) Zhang

TI__Mastermind 40656 points

Hi Charles,

That aligns with what I am seeing as well. There doesn't seem to be any additional logic referencing to the EN pin. If the open drain driver implementation is not feasible, customer may also see the TXS0102 and drive EN pin low to disable I/Os (external pullups would also no longer be needed).

Regards,

Jack

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LSF0102: Leakage from Bn to An