CC 2540 Connectivity Failure On ESD

Nir Porat

Other Parts Discussed in Thread: CC2540, LP5907

Hey,

I am using CC 2540 in my application and i am using a USB charger to charge my product.

On the input i have ESD suppressor and TVS diode which they are protecting the circuit from ESD impacts, however , on direct contact the controller resets and needed to be rebooted by pressing the power button.

What is the recommended protection needed to protect the controller from stop working?

Any particular suppressors recommended for it?

over 11 years ago

0 Fredrik K over 11 years ago

TI__Guru** 106705 points

Hi Nir,

What do you mean by direct contact? Touching the PCB or the CC2540 with a finger or ESD zapping the board?

Cheers,
Fredrik

0 Nir Porat over 11 years ago in reply to Fredrik K

Intellectual 590 points

Hey,

I am using CC 2540 with LP5907 LDO,
I have rechargeable battery which is charged using pogo pins,

the contact are not connected to the BLE directly but to the circuit 5V input.

The ESD transient is causing the reset I/O to be active and then the BLE resets.

-If i remove the 2.7Kohm resistor which is needed according to TI's spec, the BLE does not reset.

0 Fredrik K over 11 years ago in reply to Nir Porat

TI__Guru** 106705 points

How have you connected the 2.7 kohm resistor? A common mistake is to connect this as pull-up to VDD. Can you post your schematic?

0 Nir Porat over 11 years ago in reply to Fredrik K

Intellectual 590 points

it is connected to the debug connector as shown above

0 Nir Porat over 11 years ago in reply to Nir Porat

Intellectual 590 points

Any new input?

0 Nir Porat over 11 years ago in reply to Nir Porat

Intellectual 590 points

0 Fredrik K over 11 years ago in reply to Nir Porat

TI__Guru** 106705 points

Hi Nir,

If removing the 2.7 kohm resistor solves the problem, I would recommend removing it. We added this as at some point as additional protection against noise propagating into the reset pin, but in most cases it is not really required. Additionally you may consider adding an ESD diode on the reset pin.

Cheers,
Fredrik

0 Nir Porat over 11 years ago in reply to Fredrik K

Intellectual 590 points

Hey,

If i will remove it i might have issues with burning the BLE on production.

in addition esd suppressor does not help to prevent it.

is there a way to burn without reset pin connected?

Is there any recommended suppresssor

0 Fredrik K over 11 years ago in reply to Nir Porat

TI__Guru** 106705 points

Nir Porat said:
If i will remove it i might have issues with burning the BLE on production.

It really should not. Have you experienced such issues?

Nir Porat said:
in addition esd suppressor does not help to prevent it.

You have tried?

Nir Porat said:
is there a way to burn without reset pin connected?

Nir Porat said:
Is there any recommended suppresssor

Any TI ESD diode.

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CC 2540 Connectivity Failure On ESD