ESDS304: ESDS304DBVR used with UART Transceiver

Kavitha Ajay

Part Number: ESDS304
Other Parts Discussed in Thread: MAX3232, TPD2E007

Hi,

I am using ESDS304DBVR ESD diode for Max 3232 UART transceiver o/p pins TX and RX at the connector end.

and with this ESD diode i am not able to detect the device or communicate.

Once this ESD diode is removed, Max3232 ckt works fine. please let me know why and also suggest other ESD diodes if the one used here is incorrect.

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 276670 points

This is a 3.6 V diode. RS-232 signals can go up to ±15 V.

You need something like the TPD2E007.

0 Kavitha Ajay over 2 years ago in reply to Clemens Ladisch

Prodigy 60 points

Thank you, if we select a diode with Voltage ref and tie it to Max3232 Vcc, then 3.6V ESD diode holds good? something like CDSOT236-0504C. then the VIO becomes (GND-0.5) to (VCC+0.5)

0 Kavitha Ajay over 2 years ago in reply to Clemens Ladisch

Prodigy 60 points

i also checked with PESD5V0L2BT,215, where the VRWM is 5V, and VBR is max 8.2V and it works fine with that.

0 Clemens Ladisch over 2 years ago in reply to Kavitha Ajay

Guru 276670 points

In your test, the voltages were below 8.2 V. But with other devices, they can be up to ±15 V.

0 Erika Beskar over 2 years ago

TI__Prodigy 340 points

Hi Kavitha,

As you have already alluded to, the working voltage of the diode is an important consideration when selecting a diode for your application.

In case of RS-232 signals, we recommend TPD2E007DCKR which will help protect signals of ±13 V.

Please let us know if you have additional questions.

Thanks,

Erika

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ESDS304: ESDS304DBVR used with UART Transceiver