esd burst lmp91300

Fabio Giovanardi

Prodigy 20 points

Hi,

I used a small diameter sensor (4mm) with lmp91300and I have some emc problems:

esd immunity test (iec 61000-4-2): the device with 4kV is broken. I changed the Cby capacitor but I didn't see any improvements.
Burst immunity test (iec 6100-4-4): the state of the output change for about 1ms. I fixed it adding a capacitor between the output and ground, but it reduce the switching frequency of the sensor.
Conducted disturbances (iec 61000-4-6) . I can't fix the problem

Ps In the layout of NPN version I didn't place the D4 zener diode (between the supply and the output)

over 9 years ago

0 Ben Kasemsadeh over 9 years ago

TI__Genius 13650 points

Hi Fabio,
we will look into your questions and get back to you by Thursday.

0 Michael Stout over 9 years ago in reply to Ben Kasemsadeh

TI__Genius 16890 points

Hi Fabio,

Do you have the zener between the supply and ground connections? I would also put the zener between the load connection and ground.

Mike

0 Fabio Giovanardi over 9 years ago in reply to Michael Stout

Prodigy 20 points

Yes, I have the zener between the supply and ground connections and the zener between the load connection and the ground.
I read your documents about the esd protection:

www.ti.com/.../slyt492.pdf
www.ti.com/.../slva680.pdf

Thus, the zener between the output and the power supply is useful to ensure the ESD protection ?

BR
Fabio

0 Michael Stout over 9 years ago in reply to Fabio Giovanardi

TI__Genius 16890 points

Hi Fabio,

Yes, I would think it is necessary for ESD protection. It provides a path for the over voltage on that pin during an ESD event. I think all of the various designs I have seen from customers have had a zener there.

Mike

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esd burst lmp91300