THVD1450: Layout example missing resistors?

Kurumi Hasegawa

Expert 7151 points

Part Number: THVD1450
Other Parts Discussed in Thread: THVD1520

Hello, all

I have a question about THVD1450 design example and layout example.

In the datasheet, there are two pulse-proof resistors in Figure 37.

On the other hand, Figure 40 doesn’t have those pulse-proof resistors and I wander why.

I checked other datasheets and found that the datasheet of THVD15xx is similar to THVD14xx, but THVD1520 has pulse-proof resistors in both its design example (Figure 21) and layout example (Figure 24).

I assumed those resistors were simply omitted in the datasheet of THVD14xx and THVD15xx because those are not always necessary.

Is my understanding correct?

Sincerely,

Kurumi Hasegawa

over 5 years ago

0 Kurumi Hasegawa over 5 years ago

TI__Expert 7151 points

Sorry, the images are not shown correctly.

I meant those examples in the datasheet.

0 Miguel Robertson over 5 years ago in reply to Kurumi Hasegawa

TI__Guru 62920 points

Hasegawa-san,

Your understanding is correct. These resistances are not required to function, but are sometimes present in applications to help further protect the transceiver from electrical stresses coupling to the port by limiting the surge currents flowing into the IC. As such, they may be present in some typical application drawings but not others. Please let me know if this is not clear or if you have further questions.

Reagrds,
Max

0 Kurumi Hasegawa over 5 years ago in reply to Miguel Robertson

TI__Expert 7151 points

Max-san

I understand.

Thank you very much.

Regards,

Kurumi Hasegawa

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THVD1450: Layout example missing resistors?