Wednesday, December 01, 2010

CAT PUMA Pursues Image Sensor Applications

Chip Estimate: Cambridge Analog Technologies (CAT) has developed Precision Ultra Micro-power Amplification (PUMA) technology-based ADC IP applicable to image sensor applications. The company implements MIT-developed low-power switched capacitor techniques. While most switched cap circuits rely on op-amps, CAT uses zero-cross detectors (ZCD) to switch on/off capacitor charging sources:

The ZCD-based circuits are said to consume one to two orders of magnitude less power than op-amp for the same settling time and accuracy. Now power numbers are given in the article, while white papers published on the company's site suggest much smaller savings.


  1. This kind of power savings will increase the injection of spikes into the supply/ground, so it will probably generate quite some artifacts in the image. If u really want to save current without spikes use a hybrid/soft version (sure at the cost of complexity).

  2. but the precision is related to the ZCD's speed, better precision should use higher speed and more consumption. What is the real advantage of this? You can also use a dynamically biased OP-AMP.

  3. very impressive work !!!!

  4. @ "What is the real advantage of this?"

    If we just look on the numbers in the CAT's papers, they are not bad at all. Indeed, there guys present 10enob/100Msps ADC having 6.2mW power consumption and 12b-10enob/50Msps ADC consuming 4.5mW power. This is quite in-line with the best alternatives.

    If comparing with column-parallel approach, one needs to add a power of analog demux and PGA to make a fair comparison.


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