Getting 750 MHz/V VCO gain for a ring oscillator with a 1V power supply

• Mar 14, 2007

• #1

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chacha

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Hi

Is it really possible to get a VCO gain of 750MHz/V for a ring oscillator in 90nm technology with a power supply of 1V?? VCO freq range is 400M to 800M.

Thanks.

 

• Mar 14, 2007

• #2

khouly

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Re: VCO gain

ur output is 400 to 800 MHz , and ur talking about almost 8ooMHZ/v , this means that the control voltage vary about .5 volt to sweep all the range from 400 to 800 MHz

i am not familiar with 90nm process , but i think it is heard to get this tuning gain

Khouly

 

• Mar 14, 2007

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chacha

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Re: VCO gain

yes khouly.
I need this range in 0.6V.

 

• Mar 14, 2007

• #4

khouly

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Re: VCO gain

do u have models for the 90nm process
and , do u want to design differential ring oscillator or single ended

khouly

 

• Mar 14, 2007

• #5

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hung_wai_ming@hotmail.com

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VCO gain

i think it's hard to get it done across all corners
as typical ring VCO will vary almost 100% from different corners.

 

• Mar 15, 2007

• #6

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surianova

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Re: VCO gain

chacha said:

Hi

Is it really possible to get a VCO gain of 750MHz/V for a ring oscillator in 90nm technology with a power supply of 1V?? VCO freq range is 400M to 800M.

Thanks.

Click to expand...

I think quite hard to acheive that.. the VCO phase noise and jitter will be a lot. You better combine a few VCO to acheive that range.

 

• Mar 15, 2007

• #7

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chacha

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Re: VCO gain

yes khouly.
I need this range in 0.6V.

 

• Mar 15, 2007

• #8

khouly

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Re: VCO gain

it is very hard , to get i know that the ring oscillator is have wide tuning range but this wide u need two or three oscillators to achive these

if u have the models of the 90nm process , upload them , and we can try with each other

khouly

 

• Mar 15, 2007

• #9

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chacha

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Re: VCO gain

i too little skeptical about achieving this.
at this moment i dont have any models.

if anyone is having papers regarding multi band ring oscillator, pls share with me.

Thanks.

 

• Mar 15, 2007

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hung_wai_ming@hotmail.com

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VCO gain

Did u ever do any PLL or VCO before? If not, it would be too dangerous to try 90nm for the first time. 9 dead 1 survive

 

• Mar 15, 2007

• #11

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chacha

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Re: VCO gain

i have some exp in VCO design in 180nm process for UWB applications. That was an LC oscillator.
I have not done any ring oscillator till now.
What will be the major difficulties in 90nm for oscillator design??

thanks.

 

• Mar 16, 2007

• #12

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chacha

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Re: VCO gain

What are main challenges while designing wide band ring oscillator in 90nm??
If anyone is having docs pls share with me..

thanks.

 

• Mar 16, 2007

• #13

evilguy

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Re: VCO gain

for circuit simulation you can use predictive technology model (PTM) for simulation. it can be found at **broken link removed** that's the best i can get for 90nm process. the actuall fab process might not available for free.

 

• Mar 16, 2007

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ali_desidero

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Re: VCO gain

chacha said:

Hi

Is it really possible to get a VCO gain of 750MHz/V for a ring oscillator in 90nm technology with a power supply of 1V?? VCO freq range is 400M to 800M.

Thanks.

Click to expand...

you may get something working, but with bad performance and yield.

 

• Apr 1, 2008

• #15

jecyhale

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Re: VCO gain

chacha said:

Hi

Is it really possible to get a VCO gain of 750MHz/V for a ring oscillator in 90nm technology with a power supply of 1V?? VCO freq range is 400M to 800M.

Thanks.

Click to expand...

of course. Ring osc should be used.

 

• Apr 1, 2008

• #16

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vijaykarnam

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Re: VCO gain

u can achieve this VCO tuning range by using diffential charge pump stucture. With Single end charge pump, it is very difficulty to achive this arange with ur supply 1volt .

vijay

 

• May 7, 2008

• #17

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dravi99

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Re: VCO gain

Hi ,

I am working on .13um process. I designed a single ended ring oscillator. I need to know how to calc. the gain i.e. Kvco.?? At supply voltage of 1.2V this VCO runs at 1Ghz, at 2V this goes till 2Ghz. Now how do I calc Kvco. Any help will be great. If I am targetting 1GHZ/1V then what i am supposed to do?

This is the first time I am doing a PLL. What are the consideration that I need to make for a diffferntial ring osc. topology.

Any help will be appreciated.

Thanks in Advance.