significance of breakdown voltage of .18um tsmc proces

[vijith133]

hi

could anyone tell me the significance of breakdown voltage in .18um tsmc process.

what does this exactly mean..? does it annotates that the maximum vds voltage or maximum vgs voltage?

if so in .18um technology can i give the supply voltage of 3.3v with .18 micrometer channel length?

i am little bit confused about thhe design, as i am designing a cross coupled rectifier.

thanks in advance..

 

[erikl]

could anyone tell me the significance of breakdown voltage in .18um tsmc process.
what does this exactly mean..? does it annotates that the maximum vds voltage or maximum vgs voltage?

There are 2 breakdown voltages, one for Vds (depending somewhat on channel length) and another one for Vgs (depending on tox).

... in .18um technology can i give the supply voltage of 3.3v with .18 micrometer channel length?

No, definitely not. For a supply voltage of 3.3V you need the 3.3V option, which provides a tox=7nm (whereas the standard 1.8V process uses tox=3.6nm). Also, the min. channel length for 3.3V transistors will be longer than 0.18µm (usually by a factor of 2).

 

[vijith133]

thank you for your kind help..

but i would also like t clarify that , a tolerance of 10% would exist or not for the the supply voltage in .18um tsmc technology

 

[erikl]

Sure: the process is qualified for VDD±10% , the 1.8V process up to VDD=2.0V (this includes Vds and Vgs max. values).
Anyway, I'd recommend to use Lmin>0.18µm in such case - to stay on the safe side.

 

[vijith133]

Sure: the process is qualified for VDD±10% , the 1.8V process up to VDD=2.0V (this includes Vds and Vgs max. values).
Anyway, I'd recommend to use Lmin>0.18µm in such case - to stay on the safe side.

Sorry i had to poke u bother u again. I recently read a journal paper New Compact CMOS Li-Ion Battery Charger Using Charge Pump technique for Portable applications the paper says, I put the exact quotes here " This charger is implemented using TSMC 0.35 micrometer CMOS process with 5-V supply. The output voltage is almost 4.2 V, and a maximum charging current reaches 700 mA".

This completely against what you explained to me. How is it possible to use .35 micrometer technology transistor with 5 V supply. Could you pls expain in this context once more if possible. how could have they used this scheme

To your kind knowledge this paper was published in IEEE transactions on circuits and system-1.

 

[erikl]

I was talking about a 0.18µm process. Now you compare with a 0.35µm technology, which of course has different voltage ratings: the standard supply voltage is 3.3V±10% ; but usually you can get a 5V I/O option which makes use of MOSFETs with thicker gate oxide and longer than minimum gate length.

 

[vijith133]

Thank you for you reply....

As per your opinion, if I want to use a 5 V power supply for TSMC .18um process i could go for transistors with .6um or 1um for the design purpose to withstand the high voltage. the reason for my question was because my circuit is added to a chip being fabricated for TCAM design. As for the tcam we use .18um tsmc process with Vbox=12.24V (oxide breakdown voltage).

My circuit is a control circuit for battery charging purposes with 5-V supply and output voltage of 4.2V. This is another extra circuit added to the chip which is actually meant for TCAM design.

so in this case if i change the length of the transistor can i built a circuit which can withstand 5V . I meant to increase the length of the transistor from .18um to 1um or so.

 

[erikl]

As for the tcam we use .18um tsmc process with Vbox=12.24V (oxide breakdown voltage).

Ok, if you have this option.

so in this case if i change the length of the transistor can i built a circuit which can withstand 5V . I meant to increase the length of the transistor from .18um to 1um or so.

Ask TSMC for the min. gate length. Also, this info should be available with your Vbox option doc.

 

[Dominik Przyborowski]

You can use higher supply voltage but You need to provide Vgs and Vgd voltages below nominal supply value (below 1.8V). It works only for analog circuits.