| Author |
Message |
raymond_luo2003
Joined: 20 May 2004
Posts: 43
|
 11 Jun 2004 8:00 Active Inductor |
|
|
|
Hi, all,
Who has the comprehensive material on the active inductor, eg, by mos and capacitor? What's the advantage of this active inductor except the small area? Can active inductor offer the better performance than spiral or bonding wire inductor in some sense?
Thanks,
Raymond
|
|
| Back to top |
|
 |
ramesh
Joined: 19 Jan 2003
Posts: 1233
Helped: 4
|
| 11 Jun 2004 10:15 Re: Active Inductor |
|
|
|
| Spiral inductor causes EMI due to field created around it. In active inductor this very much reduced.
|
|
| Back to top |
|
|
Puppet1
Joined: 07 May 2004
Posts: 881
Helped: 2
|
| 11 Jun 2004 12:11 Re: Active Inductor |
|
|
|
there is some discussion on active inductor in razavi's books:
try both
integrated circuits for optical communications
CMOS Analog Integrated Circuits
|
|
| Back to top |
|
|
goodboy_pl
Joined: 12 Mar 2002
Posts: 243
|
| 11 Jun 2004 12:22 Re: Active Inductor |
|
|
|
Active Inductors' Plus: lower area (a little or some times!), higher Q factors (1000's!)
Active Inductors' Minus: higher noise (due to active components), lower swing or dynamic range (due to active components), higher power consumption (for biassing active mosfets)
thus in RF applications like LNA, OSC which noise or swing is important passive inductors are the only solution,
passive inductors drawbacks are: larger chip area requirement, and substrate coupling; the first problem can be solved to some extent using stacked metal layers in series (decreases resonance freq also!) and second one can be overcomed using pattern ground shield beneth the inductor.
BEST!
|
|
| Back to top |
|
|
raymond_luo2003
Joined: 20 May 2004
Posts: 43
|
| 11 Jun 2004 12:45 Active Inductor |
|
|
|
Thanks good_boy_pl
You mentioned that active inductor can have a high Q up to 1000? Can give a example or some material?
Thanks,
Raymond
|
|
| Back to top |
|
|
v_naren
Guest
|
| 11 Jun 2004 12:59 Re: Active Inductor |
|
|
|
you can refer to these 2 papers regarding active inductor and its usage.
Both are very good.
1) RF bandpass filter design based on CMOS active inductors
Yue Wu; Xiaohui Ding; Ismail, M.; Olsson, H.;
Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on [see also Circuits and Systems II: Express Briefs, IEEE Transactions on] ,Volume: 50 , Issue: 12 , Dec. 2003
Pages:942 - 949
2) A novel CMOS fully differential inductorless RF bandpass filter
Yue Wu; Ismail, M.; Olsson, H.;
Circuits and Systems, 2000. Proceedings. ISCAS 2000 Geneva. The 2000 IEEE International Symposium on ,Volume: 4 , 28-31 May 2000
Pages:149 - 152 vol.4
|
|
| Back to top |
|
|
guamak_menanak
Joined: 13 Apr 2004
Posts: 137
Location: malaysia
|
| 16 Jun 2004 6:39 Re: Active Inductor |
|
|
|
I'm also are trying to implement active inductor in my LNA design. I tried to use the active inductor as the input matching (inductive source degenerated) in the LNA design. The main problem are my NF is high (NF=9.8db) and the design is becoming unstable. The main reason is active inductor itself generate it's own noise and have it's own small signal charactersitic! This small signal can effect the performance of the LNA.
Therefore, can anyone give me some suggestion at which part that I can used active inductor on the LNA because my project is to implement Active Inductor on my design. To used active inductor as matching network is a bad design...anyone, help me 
|
|
| Back to top |
|
|
dhlee
Joined: 20 Apr 2004
Posts: 41
Helped: 4
|
| 16 Jun 2004 11:31 Re: Active Inductor |
|
|
|
The active inductor can't be used in the input matching network of LNA due to its noisy characteristics, and it is a basically small-signal equivalent inductor, so it's useless in large signal circuits like PA.
In my opinion, the active inductor can be used meritoriously for the RF chokes which need large inductance or tuning elements that can't be implemented by passive inductor.
How about using the active inductor in the series feedback element of gain-controlable LNA? The gain of LNA can be differed by the inductance of series feedback element, and It doesn't need large signal.
It will be interesting job~~ Good luck~~
|
|
| Back to top |
|
|
guamak_menanak
Joined: 13 Apr 2004
Posts: 137
Location: malaysia
|
| 16 Jun 2004 17:00 Re: Active Inductor |
|
|
|
How about using the active inductor in the series feedback element of gain-controlable LNA? The gain of LNA can be differed by the inductance of series feedback element, and It doesn't need large signal.
Can you explain more in detail how to use active L in the series feedback element of gain-controlable LNA? A paper or journal is very helpful!
Thanx is advance 
|
|
| Back to top |
|
|
DoctorX
Joined: 02 Sep 2004
Posts: 73
Location: USA
|
| 04 Sep 2004 1:44 Re: Active Inductor |
|
|
|
| raymond_luo2003 wrote: |
Thanks good_boy_pl
You mentioned that active inductor can have a high Q up to 1000? Can give a example or some material?
Thanks,
Raymond |
Try this. It is 665 tested on silicon.
|
|
| Back to top |
|
|
DoctorX
Joined: 02 Sep 2004
Posts: 73
Location: USA
|
| 11 Sep 2004 3:53 Re: Active Inductor |
|
|
|
| v_naren wrote: |
you can refer to these 2 papers regarding active inductor and its usage.
Both are very good.
1) RF bandpass filter design based on CMOS active inductors
Yue Wu; Xiaohui Ding; Ismail, M.; Olsson, H.;
2) A novel CMOS fully differential inductorless RF bandpass filter
Yue Wu; Ismail, M.; Olsson, H.;
|
The Wu & Ismail circuit has an intrincally low Q of around 5, as the source of one of the MOSFET, which has a low impedance of 1/gm, is hooked up to the gyrator feedback node.
Try H. Xiao, Karsilayan and Schaumann's circuit, it is intrincally high Q, if this is desired. --- Yes, it is just in the previous message.
|
|
| Back to top |
|
|
wylee
Joined: 17 Feb 2004
Posts: 113
Helped: 5
Location: Malaysia
|
|
| Back to top |
|
|
