TS3A5018: Ron variation with V+

Bernhard,

I measured TS3A5018 with the results below.  The trend holds as supply voltage decreases the Ron increases and is within the datasheet spec.   

Thank you,

Adam

Hello Adam,

Thank you very much for your measurements. Your results are in line with what I would have expected. In fact, they support the suspicion that the counter-intuitive trend in the datasheet is actually erronous, unless your measurements were not taken at room temperature.

Your measurement of 13,0Ω at V+=1.65V and Icom=32mA exceeds the maximum of 8Ω @ 25°C specified in the current datasheet (scds189g) by a big margin.

Please could I ask you to let us have the correct specifications at V+=1.65V, and to have the datasheet (Section 6.8) updated correspondingly. Please also include your assertion (in another thread) that the control inputs (IN and nEN) will be High-Z when V+=0V in this datasheet update.

Thank you!

Bernhard

Bernhard,

Your measurement of 13,0Ω at V+=1.65V and Icom=32mA exceeds the maximum of 8Ω @ 25°C specified in the current datasheet (scds189g) by a big margin.

The specification for 13,0Ω at V+=1.65V and Icom=32mA is greater than the typical 8Ω @ 25°C specified in the current datasheet but is within the maximum rating of 14.55Ω across temperature.  Just to be sure the device is within spec I measured it @ 85°C with the results below.

 

I went back to look why the datasheet maybe showing this counterintuitive trend and have discovered an answer.  This device was originally in 2005 and was only specified for voltage nodes V+ = 3.3 V and V+ = 2.5 V.  6 years later the device was characterized for voltage node V+ = 1.8V. 

 

Since the new characterization was done 6 years later the spec limits are tighter than the previous characterization because of more robust modeling and testing methods.  This can explain why the datasheet shows a counterintuitive trend. 

 

Thank you,

Adam

Hello Adam,

Unfortunately not. The datasheet specifies - at 25°C - a typical ron of 5.5Ω, and a maximum of 8Ω. Your interpretation is therefore incorrect. Your measurement of 13,0Ω at V+=1.65V and Icom=32mA exceeds the maximum (not typical) of 8Ω @ 25°C specified in the current datasheet (scds189g) by a big margin.

The part seems to have been incorrectly characterised at 1.8V.

Please could I again ask you to let us have the correct specifications at V+=1.65V, and to have the datasheet (Section 6.8) updated correspondingly. Please also include your assertion (in another thread) that the control inputs (IN and nEN) will be High-Z when V+=0V in this datasheet update.

Regards,

Bernhard

PS. I am struggling to respond on e2e - the buttons are not responsive. I had hoped that this would have been sorted out by this week. Hopefully this workaround reaches you.

Bernhard,

The signal switches usually only specify typical values at room temperature so I'm sorry I missed the max spec at room temp. You are correct that my measurements exceed the values stated in the datasheet.

Based on the values stated in the datasheet and my measurements above I'm going to say that the new spec is going to fall about 20 ohm typical at room temperature and 30 ohm max across full temperature.

This is going to be a major change to the datasheet so please allow 4-8 weeks for the change to post to the web.

Thank you,
Adam