I'm looking for dual channel buffer/amp with high input impedance to drive single ended 50 ohms load from 1kHz to 20MHz.
You can take a look at ADA4950-2 for your application. It has a bandwidth of 750MHz and has a dual amp in it. Also fits in the description that you wanted an embedded feedback resistor in it. It has the capability to drive your 50ohm load.
May I know what your application is so that I could give you other recommendations.
What signal swing do you need and what supply voltages are available?
Forgot to mention that input is differential.
Max input signal swing: 100mV
Supply voltage max: 15V
The output signal swing is what we need to know.
Also, since the input is differential, you would need to have a split supply unless the input never goes negative or the output is not ground referenced.
If you are in need of a buffer only (i.e. gain of 1) a 100mV swing could be handled by pretty much any OPAMP as you only need 2mA load current.
If the output swing needs to be 10V then 200mA is called for which would limit your selection considerably...
Thanks for ur reply. I don't want to use external resistance for gain setting due to mismatch issue. Is there any amplifier IC available with feedback resistors included on chip and having all the above features?
You need to be more specific.
Common mode input voltage?
Load reference voltage, i.e. what voltage is the fixed end of your 50 Ohm load hooked up to?
Is the load local or remote?
Do you have split supplies available or just a single ground referenced 15V (max)?
Input and output will be ac coupled.
Voltage gain greater than or equal to 1 is fine.
50 ohms load is referenced to ground. Going to be ac coupled, should be Ok.
Load is connected through a half meter 50 ohms cable.
Supply is single ground referenced.
I found ADA4960 can be useful here if i terminate one of the outputs. Is there any IC with two such amps...
Looks like a video buffer would be a good match.
Have a look at the AD8079.
It's a dual video buffer with internal gain resistors so you can add a source resistor to drive your transmission line.
Together with the far end termination you can easily get a gain of one at the load.
AD8079 has single ended input, I need differential input.
Thanks Chard. ADA4950-2 is meeting all my requirements. Although its input impedance (1kohm) is less than that of ADA4960 (10kohm).
I'm going to use it as I/Q IF buffer for direct conversion receiver. The receiver IC can't drive 50ohms resistive load.
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