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One important aspect of the TC217 high-resolution sensor is its ability to simultaneously capture both fields of a TV frame. Its two independently addressable memories allow separate storage of each field and operation in a variety of modes, including EIA-170 (formerly RS-170) with true interlace, EIA-170 with pseudointerlace, and nonstandard pseudointerlace with a resolution of 972 lines.

A unique multiplexer section (see Figure 3) rearranges the horizontal pixels into vertical groups of three and separates and loads the image into the two field memories. The independent addressing of each field memory provides flexibility for different modes of operation. The interdigitated layout of the memories allows each memory to share the same bank of three serial registers and associated charge detection amplifiers (see Figure 4 and the functional block diagram). Each register and associated amplifier reads out every third column of the image area (see Figure 5). The three amplifiers are optimized dual source-followers that allow the use of off-chip double-correlated clamp-sample-and-hold amplifiers for removing KTC noise.

The TC217 is built using TI-proprietary virtual-phase technology, which provides devices with high blue response, low dark signal, good uniformity, and single-phase clocking. The TC217 is characterized for operation from -10°C to 40°C.

This MOS device contains limited built-in gate protection. During storage or handling, the device leads should be shorted together or the device should be placed in conductive foam. In a circuit, unused inputs should always be connected to SUB. Under no circumstances should pin voltages exceed absolute maximum ratings. Avoid shorting OUTn to ADB during operation to prevent damage to the amplifier. The device can also be damaged if the output terminals are reverse-biased and an excessive current is allowed to flow. Specific guidelines for handling devices of this type are contained in the publication Guidelines for Handling Electrostatic-Discharge-Sensitive (ESDS) Devices and Assemblies available from Texas Instruments.

• High-Resolution, Solid-State Monochrome Image Sensor for Video or Still-Picture Photography
• Frame Transfer With Two Field Memories Allows Multimode Operation
• 1134 (H) x 486 (V) Active Elements in Image-Sensing Area
• 11-mm Image-Area Diagonal is Compatible With 2/3" Vidicon Optics
• Fast Clear Capability
• Electron-Hole Recombination Antiblooming
• Dynamic Range . . . More Than 60 dB
• High Photoresponse Uniformity
• On-Chip Cross-Coupled Resets for Easy Off-Chip Implementation of CCSH Video Signal Processing
• Solid-State Reliability With No Image Burn-in, Residual Imaging, Image Distortion, Image Lag, or Microphonics