According to the datasheet of MAX2606, Absolute maximum rating for OUT+, OUT- to GND -0.3V to (Vcc+0.6V).

And

Vout (p-p) (differential) = 2x1mA[(1kΩxRload)/(1kΩ+Rload)

I implemented the following circuit (both C2 and C3 are 2.2nF and other values are same as in the diagram) and get the single ended output and measured using the oscilloscope.

Unfortunately the output peak to peak voltage is just 300mV. (Vcc = 4.5V)

Why I can't get at output peak to peak voltage least up to 2.5V?

Please help me, I want to input the output of this to a 74F14 schmmit trigger IC.
Any suggestions please?

 

Hello,

Are you sure it is the MAX2606?
When I look at MAXIM, the MAX2606 is a RF power detector.

Bertus

 

It is a VCO and I already tested it but the issue is the output voltage which I stated in the first post.
http://www.maxim-ic.com/datasheet/index.mvp/id/2323

 

Hello,

I made the mistake in the search.
In the datasheet is given an output power of -10 dBm.
This will translate into a pp voltage of 0.1 volts into 50 Ohms.

Bertus

 

I need at least up to 2.5 Volts(p-p).
How can I get this output? What is the easiest way?
I already tried to add an transistor amplifier (2N2222, fT -> 250MHz) to get an amplified voltage around 2.5V @ 100 MHz. (Vcc for the amplifier was 5V)But it didn't work. I think I need a transistor with higher fT and I already ordered a transistor; BFR520 which is fT = 9GHz. It will take probably a week for the delivery.
But i need a quicker solution.
If I get the differential output can I achieve a higher voltage? or any other solutions?

 

Hello,

Did you also think of the RF transformer?
http://www.coilcraft.com/wideband.cfm

You can take one with CT as input and a higher number of turns for output.

Also take a look at the following amplifiers:
http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Wide_Band_Amplifiers.gif

This comes from this page of "circuit ideas":
http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Homebrew_RF_Circuit_Design_Ideas.htm


Bertus

 

Nope, i didn't try.
But Most probably these RF transformers may not available here in local market.
Anyway, what is called as "CT"?

Can I achieve the desired output voltage if I used higher Vcc (let's say 9V instead of 5V) only for the 2N2222 transistor amplifier circuit (and applying 5V as Vcc for the VCO ) and if do the calculations to choose the resistor values ?
Is there a probability damage the VCO which has a absolute maximum rating of 5.5V?

 

Hello,

CT means center tap, the transformer has a number of turns with a tap in the middle.

You can NOT run the VCO on a higher voltage as 5.5 Volts.

Bertus

PS did you see the amplifier schematics in my last post?

 

PS did you see the amplifier schematics in my last post?

I will check them now.

 

Well. None of them are available in NI multisim or Proteus ISIS simulators to simulate them. Hope the schematics are useful for the transistors that I already ordered too.

I already ordered BFR93A and BFR520. Can you confirm that they are suitable for my purpose?

 

Hello,

You could take a look at this RF amplifier:
http://www.eeweb.com/blog/circuit_projects/wide-band-rf-amplifier-with-input-range-10mhz-500mhz

The used BFR540 has a little more power available as the BFR520.

Bertus

 

Hello,

I made the mistake in the search.
In the datasheet is given an output power of -10 dBm.
This will translate into a pp voltage of 0.1 volts into 50 Ohms.

Bertus

How did you get 0.1V pp voltage for 50 ohms. It is 0.07 V. Isn't it?

 

Hello,

Yes, you are right.
I made a mistake in the calculation.
-10dBm is 0.0707 Volts into 50 Ohms.

You can use the calculators on this page to verify:
http://www.sengpielaudio.com/calculator-volt.htm

Bertus

 

Hello,

Did you also think of the RF transformer?
http://www.coilcraft.com/wideband.cfm

You can take one with CT as input and a higher number of turns for output.

Also take a look at the following amplifiers:
http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Wide_Band_Amplifiers.gif

This comes from this page of "circuit ideas":
http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Homebrew_RF_Circuit_Design_Ideas.htm


Bertus

OK. I have few W13-1TL wide band CT transformers which has an impedance ratio of 1:13.
Is it possible to input 100mV(p-p) and get a output around 3.3V (p-p) using these transformers?
This amplified output is going to a FPGA which accept LVTTL inputs. Since the FPGA has schimitt trigger inputs, I just want to amplify and use a clamping circuit to send it to the FPGA.