configuration recommendation for stable driver

Thread Starter

yef smith

Joined Aug 2, 2020
743
Hello, I am starting to design a new design for a driver.So i opened a new thread with your permission in order not to mix the old with the new.
Specifications:
BW of 2MHz will be good.
10mW input needs to be interpret into 30mA threw load coil.
The FM coil data:
sesitivity: 450 KHz/mA
3dB bandwidth 2.2MHz
resistance 2Ohm
inductance 1.5uH
i was recommended me to use a combination of AD8033 and a MOSFET
https://www.analog.com/en/products/ad8033.html#product-overviewcould you please recommend me some good configuration of two of those element .
The main thing i need it to be stable.no oscillations at high frequencies as much as possible.
Thanks.
 

MisterBill2

Joined Jan 23, 2018
18,388
OK, so it seems that this would be a driver for an electromagnet coil for a YIG oscillator. The high bandwidth for the driver amplifier will be the challenge.
I am guessing that the application is for a UHF transmitter that will deliver either FM video or fast digital data.
Certainly the actual transmitter frequency will depend on the coil current, which means that the zero-modulation current must be controlled to hold the frequency. (This is a guess)
So the driver must also be able to control the DC current as well as deliver an amplified variation.
Providing a current drive with that bandwidth to an inductive load, in addition to providing a DC response will not be simple. It might be simpler to have two driver sections, one for the DC frequency control and a second for the modulation function.
 

Thread Starter

yef smith

Joined Aug 2, 2020
743
Hello MisterBill2,Yes its for controlling a YIG which output 10GHZ.
but the FM gets DC :) ( with noise)
no no FM video just for input DC current to YIG output single good tone.

could you please recommend me a configuration so i will simulate it.
The very important part is its needs to stable as much as possible, no oscillations.
Thanks.
 

MisterBill2

Joined Jan 23, 2018
18,388
Hello MisterBill2,Yes its for controlling a YIG which output 10GHZ.
but the FM gets DC :) ( with noise)
no no FM video just for input DC current to YIG output single good tone.

could you please recommend me a configuration so i will simulate it.
The very important part is its needs to stable as much as possible, no oscillations.
Thanks.
OK, here are two options that I downloaded from another site. I hope the "insert function" here worked correctly.
They provide what looks like well designed circuits, although the power capabilities may be more than you need.

Another option will depend on if the coile changes resistance, which would be to use a regulated voltage source, since if the resistance does not change from heating then the current should not change either. The design is rather old, you will want to use a different opamp than the old 741.
I am thinking that the opamp will only need a positive supply voltage, with the negative terminal to common rather than minus 15 volts.Accurate Current Generator.jpg
 

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MisterBill2

Joined Jan 23, 2018
18,388
At this point I do not have the latest product literature to recommend a suitable single opamp. It will need to be low noise, single supply , and able to deliver perhaps as much as five milliamps. and be able to work up to two megahertz..
That should be enough to locate a suitable opamp.
 
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