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The “signal chain”—comprising links that condition, convert, and process real-world (i.e., analog) data—is the tie that binds many embedded designs. Whether a trivial application (e.g., a thermostat) or bleeding-edge rocket science (e.g., software radio), the basic structure of the chain is timeless.

What do change are the individual links that keep evolving to take advantage of the latest technology and meet the needs of new applications. What never changes is the challenge designers face to choose the solution that delivers the speed and accuracy a particular application requires while minimizing system cost and design headaches.

This month’s chip, the Quickfilter Technologies QF4A512, is a unique take on the subject. It’s a link that combines functions in a new way—one that I haven’t seen before. Does it deserve a place in your quiver of design solutions? Let’s take a closer look.

A quick glance under the hood reveals that the QF4A512 combines about two and a half links in the chain (see Figure 1). The first link is a signal-conditioning analog front-end comprising four channels worth of differential inputs, programmable gain amplifiers, antialiasing filters, and an analog multiplexer. The second link is the all-important ADC itself. The final half-link represents a piece of the processing puzzle in the form of digital finite impulse response (FIR) filters, one for each channel. The filter coefficients are stored in on-chip EEPROM so they don’t need to be reloaded every power cycle. In addition, 256 bytes of the EEPROM are available for user application.

(Click here to enlarge)

Figure 1—The Quickfilter QF4A512 is a four-channel ADC with a DSP-like difference in the form of built-in digital FIR filters.

The value of the QF4A512, indeed any integrated chip, comprises both the sum of its parts and any benefits associated with the particular combination of them. Let’s break the chip down and then put it back together to see how it stacks up.