LSF0204: LSF0204 no Verf_A power

Hugo Liu

Genius 5095 points

Part Number: LSF0204
Other Parts Discussed in Thread: SN74AVC4T774, SN74AVC4T234, TXB0104

Hi Sir,

If LSF0204 no Verf_A power, Then Verf_B=3.3V have Leakage current on Vref_A.

Is this normal? Why is Leakage there?

Hugo

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 243870 points

There is a MOSFET connected between Vref_A and Vref_B in a way that ensures that its gate voltage is at the threshold voltage above Vref_A (see below).

To disable the device, pull EN low.

0 Hugo Liu over 4 years ago in reply to Clemens Ladisch

Genius 5095 points

Hi Clemens,

EN pull Low also have Leakage on Vref_A.

Hugo

0 Clemens Ladisch over 4 years ago in reply to Hugo Liu

Guru 243870 points

Hmm, the datasheet does not actually say that EN would affect Vref_A/B in any way, only the I/Os.

It appears the LSF0204 is not designed for partial power-down applications.

The TXB0104 supports partial power-down, but has additional electrical requirements on the signal lines; for unidirectional signals, use SN74AVC4T234 or SN74AVC4T774.

0 ShreyasRao over 4 years ago in reply to Clemens Ladisch

TI__Guru 56070 points

Ioff is measured on the IO ports when either one of the supply is turned off. The datasheet test condition has both the Vref supplies to 0V.

Logic

Logic forum

LSF0204: LSF0204 no Verf_A power