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Low Power NTSC/PAL/SECAM Video Decoder with Differential CVBS Inputs

Product Status: Mass Production


The TW9990 is a low power NTSC/PAL/SECAM video decoder chip that is designed for automotive applications. It supports both single-ended and differential composite video as well as S-Video. Typical power consumption is 110mW for composite input applications, and the available power-down mode further reduces power consumption. It uses 1.8V for both analog and digital supply voltage and 3.3V for I/O power. A single 27MHz crystal is all that is needed to decode all analog video standards.

The video decoder converts base-band analog CVBS or S-Video signals into digital 8-bit 4:2:2 YCbCr video output format. It consists of an analog fron-end with input source selection, variable gain amplifier, analog-to-digital converters, a Y/C separation circuit, a multistandard color decoder (PAL BGHI, PAL M, PAL N, combination PAL N, NTSC M, NTSC 4.43 and SECAM), and synchronization circuitry. The Y/C separation is done with a high quality adaptive 4H comb filter for reduced cross color and cross luminance. The advanced synchronization processing circuitry can produce stable pictures for nonstandard and weak signals. The output of the decoder is line-locked and formatted to the ITU-R 656 output stardard with embedded sync.

The TW9990 also includs circuits to detect and process Vertical Blanking Interval (VBI) signals. It slices and processes VBI data for output through the video bus. Some information can also be retreived through the host interface.

A 2-wire serial host interface is used to simplify system integration and all functions can be controlled through this interface.


    Video Decoder
  • NTSC (M, 4.43) and PAL (B, D, G, H, I, M, N, N combination), PAL (60), SECAM support with automatic format detection
  • Software selectable analog input control allows for combinations of single-ended CVBS, differential CVBS and S-Video
  • Built-in analog anti-alias filter
  • Two 10-bit ADCs and analog clamping circuit
  • Fully programmable static gain or automatic gain control for the Y-channel
  • Programmable white peak control for the Y-channel
  • 4-H adaptive comb filter Y/C separation
  • PAL delay line for color phase error correction
  • Image enhancement with peaking and CTI
  • Digital subcarrier PLL for accurate color decoding
  • Digital Horizontal PLL for synchronization processing and pixel sampling
  • Advanced synchronization processing and sync detection for handling non-standard and weak signal
  • Programmable hue, brightness, saturation, contrast and sharpness
  • Automatic color control and color killer
  • Chroma IF compensation
  • VBI slicer supporting industrial standard data services
  • VBI data passthrough, raw ADC data output
  • Programmable output cropping

    Digital Output
  • ITU-R 601 or ITU-R 656 compatible YCbCr (4:2:2) output format

  • Short-to-Battery Detection test
  • Short-to-Ground Detection test
  • Two-wire MPU serial bus interface
  • Supports real-time control interface
  • Power save and power down mode
  • Low power consumption
  • Single 27MHz crystal for all operations
  • Supports 24.54MHz and 29.5MHz crystal for high resolution square pixel format decoding
  • 3.3V tolerant I/O
  • 1.8V/3.3V power supply
  • 32 Ld WFQFN (QFN with wettable flanks)
  • AEC-Q100 qualified


 Block Diagram


Basic Information
Production Status
Mass Production
# of Inputs
# of Channels/Device
Video DAC
Comb Filter
Bus/Output Interface
BT.656, BT601
Qualification Level
Video Decoder
Temperature Range
-40 to +105

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