MAY I JOIN YOU?

First, let me say I’m intrigued by the concept embodied in the QF4A512, namely adding digital functions to create a smart ADC. Whether connected to an MCU, DSP, or FPGA, the QF4A512 can act as a filtering coprocessor that offloads the host completely of number-crunching loops that would otherwise be a huge, or even unbearable, burden.

That being said, the concept of integration is always challenged by the necessary evil of compromise. No one-stop chip can be all things to all designs. At nearly $10 ($9.89 for 1,000 pieces), the QF4A512 will best serve applications that can take full advantage of what it has to offer in terms of resolution, speed, and filter complexity.

As for the chip itself, my main quibble is with the SPI interface, which not only seems a bit cumbersome, but also is arguably underkill for the task at hand. A conventional 8-/16-bit peripheral interface would be a welcome addition. And what the heck, maybe even throw in some FIFOs. That way the QF4A512 can work with an interrupt or DMA controller to make life even easier for the host (less overhead, relaxed timing).

One thing is for sure: If the QF4A512 fits your application, your brick wall filters will be the envy of designers forced to get by with lesser technology. You can move on to more interesting things while they’re fussing with balky breadboards or tweaking inner loops. I know you won’t gloat—much.