LMH6642: Short circuit protection above room temperature

MOSEL

Part Number: LMH6642

Hi,

The LMH6642 is stated to be short circuit protected for Vs < 6V at room temp and below. My application will see industrial temps (Up to +85 C ambient) and I need to know if I will need to design in further protection. Is there information available about short circuit protection for temperatures above room temp? If not, cold this be determined using maximum allowable power dissipation?

Thank you and best regards.

Edit: Maximum expected sourced voltage is 10V peak to peak.

over 6 years ago

0 MOSEL over 6 years ago

Intellectual 305 points

Maximum expected sourced voltage is 10V peak to peak.

0 kai klaas69 over 6 years ago in reply to MOSEL

Guru 140200 points

Hi Mosel,

I would provide a current limiting resistor in series to the output to limit the heat dissipation within the LMH6642 during a short circuit.

Kai

0 MOSEL over 6 years ago in reply to kai klaas69

Intellectual 305 points

Thanks Kai,

I'm considering it but it makes the last stage of my amplifier very power inefficient. Would like to avoid overbuilding if the inbuilt protection is sufficient since it likely necessitates another stage.

0 Sean Cashin over 6 years ago in reply to MOSEL

TI__Mastermind 23226 points

Hi Mosel,

Could you provide your amplifier circuit and indicate whether you are sourcing or sinking short circuit current? You are right, the key consideration is keeping junction temperature below 150C, calculated from the thermal resistance between the junction and the heat sink and the power dissipated from a short circuit found in figure 28 of the datasheet.

Best regards,

Sean

0 MOSEL over 6 years ago in reply to Sean Cashin

Intellectual 305 points

Hi Sean,

I believe I have figured this one out. I was able to import the model in spice, measure power dissipation for the package, and compare that against the maximum allowable for the max temperature according to the datasheet.

Thanks!

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LMH6642: Short circuit protection above room temperature