DS90UB914A-Q1: Pull down of LOCK pin

Kuramochi Tadahiko

Guru 28715 points

Part Number: DS90UB914A-Q1

Hi,

According to the datasheet, LOCK pin is TRI-STATE during PDB=LOW as below.

Should the LOCK pin be connected with pull down resistor?

If yes, how much resistors should be set?

Best Regards,

Kuramochi

over 6 years ago

0 Davor Glisic over 6 years ago

TI__Expert 7935 points

Hello-

Typically, LVCMOS outputs don't require a pull down resistor. The receiver driven by the LOCK signal would have a pull-down that would be sufficient to keep the signal below its VIH level even the the LOCK output is in tri-state.

Regards,
Davor

0 Palaniappan Manickam over 6 years ago

TI__Genius 10475 points

Hello,
LOCK is an output pin and no pull-down is needed. Please refer to table 3 in the 914A datasheet on output states and when LOCK is valid.

0 Kuramochi Tadahiko over 6 years ago in reply to Palaniappan Manickam

Guru 28715 points

Hi Team,

My customer's system has diagnostic function and LOCK signal is used it.

So they must connect the pull down resistor to output Lo during PDB=Low.

What ohms resister should they connect?

Best Regards,

Kuramochi

0 Davor Glisic over 6 years ago in reply to Kuramochi Tadahiko

TI__Expert 7935 points

Hello-

25k-100k is acceptable.

Regards,
Davor

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DS90UB914A-Q1: Pull down of LOCK pin