ChipX ventures further into mixed-signal ASICs

ChipX, the ASIC company formerly known as Chip Express, and formerly known for their metal-configured structured ASICs, is in the process of reinventing itself. The first step was to acquire the technically-solid but not well-known Oki Semiconductor ASIC unit. Then, seeing an opportunity in the industrial world for mixed-signal ASICs, the company is reaching well beyond its digital heritage to build a family of mixed-signal standard-cell ASICs for such applications as industrial controls, instrumentation and medical applications, and machine automation. Interestingly, the company is exploiting the digital background of its original, primarily Israeli, hardware design team in this effort.

The most vital step in creating a mixed-signal presence is the IP libraries. If you are building every analog function as a special product from transistors, you are not going to get far. And ChipX is indeed focusing energy on building a solid library. The most recent example of this effort is a family of digital-to-analog converters. The IP blocks offer an interesting view into how a company with a structured ASIC heritage goes analog.

According to vice president of marketing Elie Massabki, the design team early on settled on a pipelined DAC architecture. The pipelined approach is fashionable for mid-performance converters these days. But it is also, Massabki points out, very scalable. If you want to change precision, sample rate, power, or other parameters, you can reconfigure the stages, add or remove stages, or otherwise make simple changes that can be managed through metal-mask configuration—familiar ground to this design team. The mask configurations take "a couple of weeks" according to Massabki. "We ended up with a combination of metal-mask and register configuration," Massabki says. "Changes in topology require changing a metal mask. Tweaks to parameters can be done by loading a register."

Among the parameters that the design team emphasized in their design was power consumption. The converters are designed from the beginning to offer a variety of power-saving and power-down modes, to adapt to customers’ use profiles. Thus ChipX’s strategy is to do a small number of base IP blocks, and rely on a combination of metal-mask options and software-controlled registers to configure the block to a particular mixed-signal application.

There are no announcements yet, but expect to see this concept extended to analog-to-digital converters soon. It should be fascinating to see how the underlying notion of a metal-mask-configurable topology works out in the world of ADCs, where architectures vary so much over the precision/performance range.

It’s always interesting to have another serious option for mixed-signal ASICs, particularly at a time when AMIS’s acquisition by ON Semi raises questions about an important player. But when the vendor has a background in quick turn-around and relatively low-volume orders, and when it imports a technology built around metal-mask configurability, that adds to the interest.