Single chip for HD image acquisition

HD image signal processors combine image signal conditioning circuitry, a 14-bit ADC, and precision timing core for medical, industrial and scientific designs




As medical, industrial and scientific markets increasingly adopt high-definition (HD) image acquisition systems, designers of such systems must confront a host of signal-processing complexities in order to accurately capture and record high-resolution images. Analog Devices (ADI) has developed two high-performance, highly integrated 14-bit HD image signal processors: the 75 MSPS dual-channel AD9978A--the industry’s fastest-- and the 72 MSPS quad-channel ADDI7004. These single-chip solutions enable designers to create multi-channel CCD (charge-coupled device) or CMOS (complementary metal-oxide semiconductor) HD image acquisition systems that can deliver the degree of clarity, visibility and accuracy needed for today’s high-resolution requirements.
Many leading manufacturers of digital still cameras, camcorders, scanners and other imaging systems depend on Analog Devices to deliver the highest performance products with the lowest power dissipation available. Analog Devices’ 75 MSPS dual-channel AD9978A and 72 MSPS quad-channel ADDI7004 HD image signal processors enable the high-resolution, high-speed sampling of signals from advanced image sensors, while consuming very little power—280 mW (milliwatts) and 530 mW, respectively.
“Until today, high-performance imaging system designers were forced to use multiple high-power components to sample image signals at HD rates,” said Stuart Boyd, product line director, Digital Imaging Systems at Analog Devices. “By integrating high-performance signal conditioning circuitry, a 14-bit data converter, and a precision timing core into a single HD image acquisition solution, designers can achieve an unequalled combination of speed and accuracy in high-speed, high-resolution digital imaging systems, while eliminating the power dissipation limitations that restrict portability and increase design cost.”

Accurate and Sharp HD Images for High-speed Applications

The AD9978A and ADDI7004 devices extend Analog Devices’ family of AD997x image signal processors for high-speed digital imaging applications. Each channel integrates a complete AFE comprising a black-level clamp, a CDS (correlated double sampler), a 1bit VGA, and a 14bit ADC. Analog Devices’ Precision Timing core provides adjustments for the CDS and SHA (sample-and-hold amplifier) clocks with 210ps resolution at 75 MHz (ADD9978A) and 217 ps at 72 MHz (ADDI7004). The AD9978A and ADDI7004 also contain a reduced range LVDS (low-voltage differential signaling) interface for the image-data outputs to increase performance and reduce EMI issues.
The power consumption of each device is proportional to its sampling frequency. Both high-resolution image signal processors support designers’ efforts to standardize their image sensor interface designs across multiple platforms, eliminating the need to change or add additional components and reducing overall system cost across several models. Additionally, the AD9978A offers pin-for-pin compatibility with the industry-standard AD9978 14-bit CCD signal processor, enabling designers to easily change existing designs to deliver high-end performance.
The dual channel AD9978A costs $25.32 while the quad channel ADDI7004 costs $48.12.