THVD1452: Can device drive load of 50 ohms/additional ESD

Adam Daluga

Expert 6385 points

Part Number: THVD1452

Hello,

I had a few questions regarding the THVD1452DGSR.

For RS-485 the resistive terminators typically have values from 120 to 130 Ω.in the line we have two resistors so we have 60 Ω.

In case we want to use resistive terminators of 100 Ω (in parallel - 50 Ω).Can this device drive a load of 50 Ω?

In case we don’t need to protect against surges transients only ESD do I need to add any external device protection for ESD?

Thanks,

Adam

over 5 years ago

0 Hao L over 5 years ago

TI__Mastermind 25705 points

Adam,

Yes, THVD1452 can work with a 50Ohm load. You can refer to Figure 1 and Figure 2 of section 7.9 (page 12) on the datasheet for various load conditions.

The device has integrated some ESD protection, like +/-18kV IEC 61000-4-2 on bus pins, which should be enough for many industrial applications. However please check all kinds of transient overstress conditions the application to make sure they don't exceed the level THVD1452 can support.

Regards,

Hao

0 Adam Daluga over 5 years ago in reply to Hao L

TI__Expert 6385 points

Regarding THVD1452 that need to drive 50Ohm load.Thanks for guiding me to the right part of the datasheet, I'm operating at 3.3 so i think that figure 3/4 are the right ones for me. In table 7.4 it says that the minimum RL is 54ohm ,so, I don’t know if I can change the load to 50ohm. What do you think?

Thanks,
Adam

0 Hao L over 5 years ago in reply to Adam Daluga

TI__Mastermind 25705 points

Adam,

This minimum RL value is the load condition that the device meets the specification on the datasheet. For example, the driver rise/fall time is measured with 54Ohm load in section 7.8. In other words, THVD1452 can operate with 50Ohm, which might lead to some specification violation. I hope this makes sense to you.

Regards,

Hao

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THVD1452: Can device drive load of 50 ohms/additional ESD