amplify 2MHz sin wave from 1.45-1.8V to 0-3.3V

[nbuzs]

3.3vpp

How can I amplify an sin waveform with vpp from 1.45V-1.8V to 0-3.3V vpp at the freuqency of 2MHz?
a simple stage of amplifer enough?
if yes, how should I configure it?

Thanks and Regards!

 

[AdvaRes]

amplify sin

How can I amplify an sin waveform with vpp from 1.45V-1.8V to 0-3.3V vpp at the freuqency of 2MHz?
a simple stage of amplifer enough?
if yes, how should I configure it?

Thanks and Regards!

You have to eliminate the 1.45 offset using a comparator and then amplify the resulting signal.

 

[FvM]

sinus wave with dac

eliminate the 1.45 offset using a comparator

???

I think, you should use a one-transistor common emitter stage. Gain can be set by input series resistor in combination with a feedback resistor.

 

[AdvaRes]

eliminate the 1.45 offset using a comparator

???

I think, you should use a one-transistor common emitter stage. Gain can be set by input series resistor in combination with a feedback resistor.

Sorry,
I meant substractor not comparator.

Why are you surprised FvM is it because of this ?
Could you explain your solution ?
Do u judge it better then meine?

 

[FvM]

A substractor is O.K. of course. I didn't imagine, what may have been meant.

With a continuous input signal, simple AC coupling is actually sufficient. The output can be biased independently of input offset. I assumed however, that something like a stable clock source is involved. With a fast varying signal, a subtractor respectively level shifter may be a better solution.

 

[nbuzs]

Thank AdvaRes and FvM.

Maybe I didn't express very clearly


The picture is my circuit. the DAC is current output, Iout and Ioutb is terminated to 1.8V through 50 O Resistors. And the Iout + Ioutb =10mA. (Painted with black).

The painted RED line is the part I designed to amplify the DAC output signal to be a 0-3.3V-Vpp sin wave.

Any Suggestions

 

[FvM]

I would expect that you are utiliziing the full differential DAC output range of +/- 500 mV rather than 0.35V, as said. The first design step is to define an exact mapping to amplifier output voltage. Then you can calculate gain and offset resistor dimensoning. If the bipolar DAC output shall be mapped to 0..3.3V, a 1.65 V offset is needed. Connecting the reference resistor to +1.65V instead of ground or using a divdider would achieve this.

The circuit, as shown, could give e. g. -3.3..+3.3 V output voltage. If the 0 V must not be reached exactly, a rail-to-rail OP may be used.

 

[LvW]

Up to now, I did not look into your circuit resp. your problem in detail, however, just one comment: Do you neglect the resistive path in parallel to the 50 ohms ?

 

[FvM]

Do you neglect the resistive path in parallel to the 50 ohms ?

It has to be considered in an exact gain calculation, of course.

 

[nbuzs]

thanks all!
I take a material from TI as a reference.
The Circuit is in page 2.

 

[nbuzs]

Up to now, I did not look into your circuit resp. your problem in detail, however, just one comment: Do you neglect the resistive path in parallel to the 50 ohms ?

yes, I neglect it.

 

[arsenal]

try attached schematic, tune r3 such that half vdd is added, make sure ur amp is rail-to-rail.

 

[nbuzs]

Thank you, arsenal.
I'm gonna to try