How many times have we created a circuit that needed just one more NAND gate or inverter?  It didn't make sense to add another complete hex inverter or quad NAND-gate package, so we'd rework a design, maybe cram something into software, or give up and just add another IC. But sometimes it's easier and less expensive to add one logic element rather than rework an FPGA design or thousands of lines of code.

Last week I discovered the TinyLogic family of ICs from Fairchild Semiconductor that includes an inverter, NAND gates, OR gates, and configurable functions. Yes, that's one logic function per chip in either 5-pin SC70 or Fairchild's 6-contact MicroPak surface-mount packages. The latter measures about 1.5 by 1.0 mm. So if you need "just one more gate" you can drop in one of these small devices. Likely you can guess that the company aims these small devices at manufacturers of cell phones, MP-3 players and other small consumer-electronic devices. But anyone with a tight design and a low power budget can use them to their advantages.

The Fairchild TinyLogic family list includes other functions such as open-drain and three-state buffers, logic decoders, flip-flops, and latches, but I never found information about them. Perhaps they're already in the pipeline and will come along soon.

The TinyLogic ICs use an advanced CMOS technology that lets them operate with a supply-voltage range of 0.9 to 3.6V, yet they can drive up to 24mA, and have low propagation delays--on the order of a few nanoseconds. Fairchild has other logic functions in the TinyLogic family, too.  For more information, visit: www.fairchildsemi.com/products/logic/tinylogic. You can download a TinyLogic product-line flyer at: www.fairchildsemi.com/collateral/logic/tinylogic_selection_guide_5-9-07.pdf.

Have you had to solve the I-just-need-one-more-gate problem?  Share your experiences with us. --Jon Titus