LSF0102: about LSF0102 Vref

Vera Mao

Part Number: LSF0102
Other Parts Discussed in Thread: SN74AVC4T774

hi dear supporting team,

could we supply 3.3V to Vref_A &Vref_B? customer want to operate it on this way and use this chip as a buffer. tks a lot!

over 7 years ago

0 Clemens Ladisch over 7 years ago

Guru 317060 points

Vref_B must be at least 0.8 V higher than Vref_A.

In any case, LSF devices are passive switches (see Voltage-Level Translation With the LSF Family (SLVA675)), so they do not behave like a buffer.

0 Emrys Maier over 7 years ago

TI__Guru* 97046 points

Hi Vera,
Clemens is correct.

Additionally, there is a new video series on the LSF series of translators that will help you to understand them. Please check it out: training.ti.com/LogicMinute

0 Vera Mao over 7 years ago in reply to Emrys Maier

TI__Expert 5065 points

hi Clemens and Maier,
thank you for the reply!
actually customer's application scenario is as below: because the SPI trace is too long and have big reflection, they want to get a SPI buffer, and with 40Msps speed, 3.3V. I am promoting SN74AVC4T774, could this one have same voltage on both side? tks a lot!

0 Clemens Ladisch over 7 years ago in reply to Vera Mao

Guru 317060 points

The AVC4T774 allows both sides to have the same Vcc.

SPI signals typically are unidirectional. Is this the case in this circuit? (Then you could use simple buffers.)

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LSF0102: about LSF0102 Vref