# Voltage Amplifier Av=5400 ,specified bandwidth. Solutions?

#### Elena Grigorița

Joined May 8, 2019
11
I need to design a sinusiodal voltage amplifier with a voltage gain of 5400,from 5mV to 27 V. Wich is a better solution , to design it with transistors or with OA?

#### Ylli

Joined Nov 13, 2015
933
This will turn into a full fledged microphone input / power amp output. As someone else told you, 27v rms into 16 ohms is 46 watts. You could do the whole thing with transistors, or you could use an op-amp and some transistors, or you could use transistors/op-amps and an integrated power amp module.

It's not a simple project.

#### BobTPH

Joined Jun 5, 2013
2,348
Frequency?

Bob

#### Elena Grigorița

Joined May 8, 2019
11
This will turn into a full fledged microphone input / power amp output. As someone else told you, 27v rms into 16 ohms is 46 watts. You could do the whole thing with transistors, or you could use an op-amp and some transistors, or you could use transistors/op-amps and an integrated power amp module.

It's not a simple project.
I designed it with 2 op amps , non inverting amplifiers , and it works ok,I have 27 V from 5mV , but I didn't count load resistance . When I place it , the output voltage is limited to 400mV. Why?

#### Elena Grigorița

Joined May 8, 2019
11

Joined Mar 10, 2018
4,057
What is value of load R, is it 16 Ohms ? If thats the case at 27V OpAmp would
have to supply ~ 1.7A

What opamps are you using ?

Regards, Dana.

#### Elena Grigorița

Joined May 8, 2019
11
What is value of load R, is it 16 Ohms ? If thats the case at 27V OpAmp would
have to supply ~ 1.7A

What opamps are you using ?

Regards, Dana.
Load resistance is 16 ohms.
For the first stage I use a LM741 with a supply of +/-15 and for the second stage OPA445/BB , supply +/-40.
I don't really know how to choose the right OpAmps.

#### Ylli

Joined Nov 13, 2015
933
For the output device, you could look at the LM3886 running with +/- 45 volt rails. It's not spec'd with a 16 ohm load, but I should expect it to do the job.