LSF0102-Q1: LSSF0102 Pull up resistor

Dilip Namdeo Mohol

Intellectual 1980 points

Part Number: LSF0102-Q1

There is a recommendation to use 300Kohm between VREFB and 5V,why is this needed?

Our application is 5V to 3.3V translation,

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 317000 points

This resistor is needed to limit the current that flows into Vref_B and out of Vref_A, and to drop the voltage at the EN pin to V_GS(th) above Vref_A.

See [FAQ] How do the LSF translators work?

0 Dilip Namdeo Mohol over 2 years ago in reply to Clemens Ladisch

TI__Intellectual 1980 points

Hi Clemens,

What will be the impact of not having it? . Customer has missed provision in PCB !.

Regards

Dilip

0 Clemens Ladisch over 2 years ago in reply to Dilip Namdeo Mohol

Guru 317000 points

A-side output signals will not be clamped tp 3.3 V.

The current flowing out of Vref_A and into the 3.3 V supply is not limited. If the supply cannot sink this current, its voltage might rise, and damage any devices connected to it.

Logic

Logic forum

LSF0102-Q1: LSSF0102 Pull up resistor