SN65HVD256: Can RXD terminal be connected to a input of 3.3V MCU directly?

Kazuya Nakai59

Guru 20130 points

Part Number: SN65HVD256

Hello guys,

One of our customers is considering using SN65HVD256 with 3.3V CPU like Figure 22 in the device datasheet(SLLSEA2D). .

At the combination, can RXD signal output of SN65HVD256 be connected to a input terminal of the 3.3V CPU directly?

In the case, is 5V tolerant needed on the CPU input terminal?

Your reply would be much appreciated.

Best regards,

Kazuya Nakai.

over 5 years ago

0 Eric Schott1 over 5 years ago

TI__Mastermind 48215 points

Hi Kazuya,

The RXD pin uses VRXD to reference the output voltage. If you supply VRXD with 3.3V, the RXD pin will drive up to this voltage.

Note that TXD is weakly pulled up to Vcc internally regardless of VRXD. A small current from this pin to a lower voltage controller can be expected.

Let me know if this answers your question.

Regards,
Eric

0 Kazuya Nakai59 over 5 years ago in reply to Eric Schott1

Guru 20130 points

Hi Eric,

Thank you very much for the prompt reply. I understood it.

Best regards,
Kazuya Nakai.

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SN65HVD256: Can RXD terminal be connected to a input of 3.3V MCU directly?