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LSF0204: LSF0204

Rohini Esakki
Prodigy 50 points
Part Number: LSF0204
Other Parts Discussed in Thread: LSF0108

Tool/software:

Hi Team,

I had gone through LSF0204 Translator working

Below points are not very clear to me and I would require a detailed explanation on this

1. How RA1 is not required if the sink current is lesser than 1uA

2. what is the voltage level of A1 at the time and how

I have one more query

Below is my application

We have a single LDO on board 3.3V it will be connected to VREFB and since Target I/O is not always<=VREFB+0.8 we cannot connect that voltage to VREFA directly

In this case, can I use voltage divider from LDO for VREF_A?

I see the LDO should be capable to sink the current (Vref_B - Vref_A - 0.8V) / 200kΩ.

If VREFA LDO doesn't support sinking current I could add a pull_down to VREFA. will it allow me to use single LDO for both VREFA & VREFB?

Awaiting for your reply

Thanks,

Rohini

  • 0
    TI__Mastermind 40866 points

    Hello Rohini,

    1.) The >1uA is a good quantifiable value for small leakage, at which the voltage at A-side will be clamped at VREFA, due to the specific biasing of VREFB shorted to EN. Section 3 of this app note: https://www.ti.com/lit/an/scea144/scea144.pdf?ts=1745613056245 provides example if excessive leakage were to occur and what behavior we can expect at the A-side outputs. 

    2.) Yes, you may see section 9.2.3 of the LSF0108 datasheet where single supply translation is used. This way the leakage current flows through pulldown to GND instead of sinking into an LDO at VREFA side. 

    Regards,

    Jack