ISO1410: ISO1410BDW overheating

Abraham Perez Trujillo

Part Number: ISO1410

I'm using ISO1410BDW in a custom design based on "ISO1410DW evaluation module". The Integrated circuit comes to 50 Celsius degree, The R4 is connected and the DNI components are no connected except the TVS in A and B terminals.

The transmit speed is 100kHz.

The ambient temperature is 29 C and temperature was measured with a thermographic camera.

Vcc1= 5V, Vcc2 =3.3

The current Icc1 and Icc2 are 130mA

Is this a normal functional temperature?

is there any technique to make the IC colder?

over 3 years ago

0 Lucas Schulte9 over 3 years ago

TI__Expert 6955 points

Abraham,

The ISO1410 should not be drawing this much current and therefore should not be getting this hot. I have a few questions to help understand the situation further.

1. Did you add a TVS diode to the EVM? If so, what is the part number? Can you try removing the TVS diode and measuring current again?

2. Is there anything on the RS485 bus besides the EVM? If so, can you measure the current with the EVM only and nothing else on the RS485 bus?

2. Can you measure Icc1 and Icc2 separately?

3. Can you provide an image of the EVM you have with the part number of the ISO1410 clear in the picture?

Respectfully,

Lucas Schulte

0 Abraham Perez Trujillo over 3 years ago in reply to Lucas Schulte9

Prodigy 60 points

HI.

The TVS model is CDSOT23-SM712.

icc2= 130mA with TVS.

Icc2 = 60mA without TVS

icc1 = 130mA

Thanks

0 Lucas Schulte9 over 3 years ago in reply to Abraham Perez Trujillo

TI__Expert 6955 points

Abraham,

It appears that the TVS diode is causing a negative effect with the ISO1410 being that there is a big difference in Icc2 current. It appears that the ISO1410 may have even been damaged since Icc1 should not be that high.

I recommend replacing this particular ISO1410 with a new one, leaving the TVS diode unpopulated, and retaking measurements.

Respectfully,

Lucas

0 Abraham Perez Trujillo over 3 years ago in reply to Lucas Schulte9

Prodigy 60 points

Lucas

We need a TVS for EMC tests, Could you recommend a TVS Model?

Thanks

Abraham

0 Lucas Schulte9 over 3 years ago in reply to Abraham Perez Trujillo

TI__Expert 6955 points

Abraham,

The SM712 should work just fine as it is meant to comply with the RS485 hardware protocol. Something else here has most likely caused damage to the ISO1410. Could be the power supply or something on the RS485 bus. The goal is to eliminate variables for now and see what has caused this.

Respectfully,

Lucas

0 Abraham Perez Trujillo over 3 years ago in reply to Lucas Schulte9

Prodigy 60 points

Lucas

Thanks for your help.

The problem with icc1 was for a pull down resistors in the configuration jumpers.

The Icc1 is about 6mA now.

We haven't test the SM712.

Thanks,

Abraham

0 Lucas Schulte9 over 3 years ago in reply to Abraham Perez Trujillo

TI__Expert 6955 points

Abraham,

I'm glad you found the problem for Icc1. Please feel free to let us know if you have any further issues.

Respectfully,

Lucas

0 Abraham Perez Trujillo over 3 years ago in reply to Lucas Schulte9

Prodigy 60 points

Lucas,

I tested the RS485 with the TVS but the icc2 = 80 mA.

is this a normal current?

Thanks

Abraham

0 Lucas Schulte9 over 3 years ago in reply to Abraham Perez Trujillo

TI__Expert 6955 points

Abraham,

This current consumption fits in the expected current consumption on a loaded bus.

Respectfully,

Lucas

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ISO1410: ISO1410BDW overheating