Electronic Design

Adding A FIR Filter After An ADC Gets Simpler

The QF1D512 SavFIRe configurable finite impulse response (FIR) filter chip can follow any analog-to-digital converter (ADC) in industrial monitoring applications like vibration sensing, flow measurement and leak detection, medical patient monitoring and diagnostics, seismic, and sonar.

Drawing the "Sav" part of its name from "simple and versatile," this Quickfilter chip also can be used as a co-processor device for controllers that have embedded ADCs. Its companion Development Kit, QF1D512-DK, enables the device to be configured for almost any ADC up to 24 bits (see the figure).

A variety of precision filters can be quickly designed without the need to write code. The development-kit board has an on-board ADC to allow operation "out of the box." It also lets users add their own preferred ADC or ADCs. Similarly, the development board can be connected to the user's own host microcontroller.

With the QF1D512 and the kit, designers can build an in-circuit reprogrammable 512-tap symmetric or 256-tap non-symmetric digital FIR filter with 12- to 24-bit data words and coefficients up to 32 bits. It runs at data rates from 10 samples/s to 500 ksamples/s. The interface is a four-wire serial peripheral interface (SPI).

SavFIRe follows Quickfilter's QF4A512-IC programmable signal converter and its development kit, introduced late last year. The QF4A512-IC goes ahead of the ADC and converts up to four analog signals to separate digital bit streams and then allows the bit streams to be filtered simultaneously. In both cases, the development kit is the key to the product's utility. The SavFIRe retains the utility of the earlier product's kit, with an enhanced GUI.

The QF1D512 comes in a 3- by 3-mm quad flat no-lead (QFN) package and is characterized over the industrial temperature range. It costs $2.98 in 1000-piece quantities.


Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.