16 January 2022

CMOS vs CCD

In the late 1960s and early 1970s, CCD and CMOS image sensor technologies were developed. CMOS performance was limited at the time due to available lithography technology, allowing CCDs to dominate for the next 25 years. CCD and CMOS image sensors both convert light into electrons by capturing light photons with thousands. If not millions, of light capturing wells knowns as photosites. When capturing an image, the photosites are exposed to collect photons and store them as an electrical signal. 

What is CMOS?

A CMOS sensor is a type of digital sensor. CMOS stands for complementary metal-oxide-semiconductor. At the pixel site, the CMOS sensor converts the charge from a photosensitive pixel to a voltage. The signal is then multiplexed to multiple on-chip digitals to the analog converters by row and column. CMOS sensors are fast, have low sensitivity.

What is CCD?

CCD is a technology that has made incremental advances in device design, materials, and fabrication technology.  CCD sensors quantum efficiency has steadily increased, while dark current and pixel size have decreased, operating voltages have decreased and signal handling has improved. And their companion circuits have become more integrated, making CCD easier to use and allowing for a faster time to market. CCD now provides better performance while consuming less power.

CMOS vs CCD | Difference between CMOS and CCD:

Noise:

CCD sensors produce images with high resolution and low noise. CMOS sensors are typically more sensitive to noise.

Power:

CCD sensor can consume up to 100 times the power of an equivalent CMOS sensor.

Sensitivity:

Because each photosite on a CMOS sensor has several transistors next to it, the light sensitivity of a CMOS chip is lower because many photons hit the transistors rather than the photosite.

Cost:

CMOS sensors are less expensive to produce than CCD sensors because they can be manufactured on most standard silicon production lines.

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