Maker Pro
Maker Pro

high frequency amplifier

mahin

May 2, 2012
11
Joined
May 2, 2012
Messages
11
hi everybody
i need an amplifier circuit:
***output impedance of signal generator(is available)=600 ohms
***load has capacitive impedance and very low (i don't know exact value) so output impedance of amplifier should be =<10 ohms.
***frequency range is 100-500 kHz.
 

john monks

Mar 9, 2012
693
Joined
Mar 9, 2012
Messages
693
Have you considered using an operational amplifier?
What gain do you need?
What is your application?
 

Electrobrains

Jan 2, 2012
259
Joined
Jan 2, 2012
Messages
259
You could use a power operational amplifier like the Apex/Cirrus type PA16.
It has 350kHz Power Bandwidth (in 10 Ohm), but costs a bit.

Or look at a cheaper, maybe still useful type: OPA548T

Or you take a faster, cheaper amplifier and build your own power stage to it.
 
Last edited:

Alchymist

Apr 16, 2011
26
Joined
Apr 16, 2011
Messages
26
Use a darlington pair and configure it for an emitter follower output.
 

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
Joined
May 8, 2012
Messages
4,960
You didn't state what output voltage (PP) you need and what the waveform will be, Sin, Square, Triangle ? Does the signal have go negative?
 

mahin

May 2, 2012
11
Joined
May 2, 2012
Messages
11
You didn't state what output voltage (PP) you need and what the waveform will be, Sin, Square, Triangle ? Does the signal have go negative?

sine and output=<25v, and....very low output impedance (5-10 ohms). have negative voltage.
 

mahin

May 2, 2012
11
Joined
May 2, 2012
Messages
11
You could use a power operational amplifier like the Apex/Cirrus type PA16.
It has 350kHz Power Bandwidth (in 10 Ohm), but costs a bit.

Or look at a cheaper, maybe still useful type: OPA548eTe

Or you take a faster, cheaper amhplifier and build your owns power stage to it.

thank you, do you know output impedance of opa548a? it isn't in datasheet.
 

Electrobrains

Jan 2, 2012
259
Joined
Jan 2, 2012
Messages
259
thank you, do you know output impedance of opa548a? it isn't in datasheet.
You have to calculate that from your own given conditions and the specs and diagrams in the data sheet (MAXIMUM OUTPUT VOLTAGE SWING vs FREQUENCY, MAXIMUM POWER DISSIPATION vs AMBIENT TEMPERATURE, SAFE OPERATING AREA, OUTPUT VOLTAGE SWING vs OUTPUT CURRENT etc.)

Or, make it practical - buy one and test it (cheapest place found on ebay, but in China)
 

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
Joined
May 8, 2012
Messages
4,960
Or look at a cheaper, maybe still useful type: OPA548T

Impressive OpAmp!
Found this in the data sheet... " A SPICE macromodel is available for design analysis."

It's not in the data sheet. Do you know where it can be downloaded from?

Thanks,

Chris

Edit: Found it. See next post.
 
Last edited:

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
Joined
May 8, 2012
Messages
4,960
You didn't state what output voltage (PP) you need and what the waveform will be, Sin, Square, Triangle ? Does the signal have go negative?

sine and output=<25v, and....very low output impedance (5-10 ohms). have negative voltage.

What's the max VPP output of your Gen when terminated into 600Ω?
 
Top