Simple DDS amp/buffer

[Wirehead]

Hi All,

I've been brewing on a simple DDS amp/buffer for those cheap ebay AD9850 modules. I'm only focusing on a sine wave at the moment, as that's what I'll mostly use in my audio stuff. (I can later add something with a 74hc14 and the same style amp/buffer).
I just made up something quick with an NE5539 (wide bandwidth, high slew rate op amp) and a BUF634 buffer to drive loads that demand it. 50Ohm output impedance; 10Hz <-> 10Mhz.
Anywho, it works pretty good (on breadboard, not ideal at high bandwidths for the NE5539) - so I'm looking to transfer this over to a small PCB. Planning to go SMD; but that NE5539 is _old_.

So, anyone have a suggestion for a replacement? Looking for something that has an equal (or better) bandwidth range; but comes in SMD; better or equal slew rate (keeping those square waves in mind in the future..); same for the gain bandwidth.

If I make a PCB, I'll open-source it. It would be nice if you can get samples of the parts in question. That way other people can build it pretty cheap as well..  I've attached a schematic and some scope shots. Output is -pretty- linear. Hey; it doesn't have an AGC, but it's cheap and good enough 

[quantalume]

I'm using the ADA4857-1 in the SOIC-8 package for the same purpose. It seems to perform fine through 30 MHz at a gain of 4, which gives me just over 1 VRMS into 50 ohms. Analog Devices also have a universal evaluation PCB available for SOIC-8 high-speed op amps, the UG-101. It has SMA input, output and disable interfaces. It's a little pricey (USD 21), but it is a good study on proper RF PCB design.

[Farley]

You might take a look at the LMH6703 from TI.

[Wirehead]

Thanks for the suggestions - ADA4857 looks nice; but the LMH6703 looks like a very good match - even when adding a decent amount of gain. (Vout 4V-pp). Couple that with the fact that samples from TI reach me very fast and without any hassle. Winner