Feb 20, 2011

The Power of Simplicity

One of the first projects I did straight out of school did not make sense to me.

I and another RCG (recent college graduate) were told to build a 6MHz video filter in .6u BiCMOS process. Our manager came up with a simple scheme of sallen key biaquads and used a simple bipolar source follower as the opamp. (well there was some local feedback but lets not get there) We protested - we wanted to build a fancy schmancy folded fully-differential cascode opamp. Our manager stood firm. The product was supposed to cost only 60c and replace the present solution of using discrete Ls and Cs by our customers. Apparently these customers all used custom solutions with discrete bulky components and we were going to "IC" it.

So we built this simple video filter family (there were multiple bandwidths for the different standards - NTSC and also different gain values etc) which consisted of 6th order filter made up of biquads. It had 2 trim steps for Bandgap reference and temco and some cool equalizer with a nice BiCMOS video driver. We did such a great job that the part worked first time met all specs and sampled to customers ahead of time. Turns out that simple IC sold more than 15mil units in the first year of its introduction.

Interestingly, another engineer was given the task of building a filter family with tighter specs - ladder filters, fully differential configuration and 5 trim steps. The firm thought that they good enter the professional video market as well. Turns out neither the value proposition nor the costing worked out so this complicated product never made it big.

Two lessons
a) The power of integrated circuit comes from ability to replace discrete bulky components with a clear value proposition.
b) KISS. Doesn't have to be cutting edge but has to have a clear value proposition for the customer. Lets see how a DSP person responds to this comment

Footnote: The product won best product award at EEDN in 1996.

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