Need structure and method of designing VCO output buffer

[eng_islam]

VCO output buffer

plz suggest a structures and method of design for VCO output buffer, im working on 1.8 v supply and 2.4 GHZ frequency

 

[hrkhari]

Re: VCO output buffer

Try an open drain buffer with 50Ohms of termination.

Rgds

 

[STOIKOV]

Re: VCO output buffer

how's the open drain implemented in CMOS ? I'm also interested in a buffer of a 900MHz vco, its output signal is sinusoidal and need square wave.

 

[eng_Semi]

Re: VCO output buffer

Try an open drain buffer with 50Ohms of termination.

Rgds

I think that 50Ohm is a very low load and it may be overestimated.

If u will drive a divider, u may use Source Follower stage, but it will consume higher power. U may read about it in Gray & Meyer

 

[STOIKOV]

Re: VCO output buffer

thanks,
what buffer topology you use in your 2.4GHz vco ? I'm using a differential ring vco and the output signal is low in amplitud and sinusoidal that's why I need a buffer.

 

[montage3000]

VCO output buffer

souce follower buffer is good/or CML with resistor and inductor loading to boost BW

 

[eng_islam]

Re: VCO output buffer

Do u have ideas about the CML output buffer "its topology, design issuses,......"
i will be greatfull if u send something related to this

 

[suria3]

Re: VCO output buffer

Do u have ideas about the CML output buffer "its topology, design issuses,......"
i will be greatfull if u send something related to this

Visit the web sites of establish companies like Texas, Maxim to find out the application notes on CML buffer and also through net resourses as well.

 

[laglead]

Re: VCO output buffer

why don't anyone suggest the use of inverter as buffer?
It's frequency cannot meet requirement? e.g. 2.4GHz?

 

[selvaraja]

Re: VCO output buffer

buffer stage is to convert the output signal from the
VCO core to a rail-to-rail switching signal . This can be achieved by the use of a two-stage buffer.An active current mirror makes the input stage, which serves both as a differential to single-ended converter and an amplifier. second stage the inverter is designed to make the output signal fully rail-to-rail switching.

 

[adwxl]

Re: VCO output buffer

How to reduce the output amplitude by buffer circuits?Thanks.

 

[jfyan]

Re: VCO output buffer

Do u have ideas about the CML output buffer "its topology, design issuses,......"
i will be greatfull if u send something related to this

HI,
if you need some ideas about high speed CML output buffer, i suggest you to read some papers writen Payam Heydari, who has his own web page.
best.
jeff yan

 

[shaikhsarfraz]

Re: VCO output buffer

hi,
For designing o/p buffer for VCO you can go for CML bufers.

Although for 2.4 GHz you can also use a differential pair.

thanks
sarfraz

 

[haoyun]

VCO output buffer

Hi jfyan,
have you received my ebook?
why don't you sent to me your ebook?
haoyun
nettmann_2002(at)zahoo.de

Added after 10 seconds:

Hi jfyan,
have you received my ebook?
why don't you sent to me your ebook?
haoyun
nettmann_2002(at)yahoo.de