U4460BG-D

The U4460BG-D has the following features including Active carrier generation by FPLL principle(frequency-phase-locked-loop) for true synchronous demodulation;Very linear video demodulation, good pulse response and excellent intermodulation figures;VCD operates on picture carrier frequency;Alignment-free AFC, no external reference circuit;VIF-AGC with peak sync. detection;Tuner AGC with adjustable take over point;5 V supply voltage; low power consumption;Relevant pinning is compatible with the TDA4474 /71 video-/ sound IF combination.

The U4460BG is an integrated bipolar circuit for video IF(VIF) signal processing in TV/VCR and multimedia applications.The U4460BG-D processes all TV video IF signals with negative modulation (e.g., B/G standard).The video IF signal (VIF) is fed through a SAW filter to the VIF input (Pin 5-6). The VIF amplifier consists of three AC-coupled amplifier stages. Each differential amplifier is gain controlled by the automatic gain control (VIF-AGC). Output signal of the VIF amplifier is applied to  the  FPLL  carrier  generation  and  the  video demodulator.At Pin 7, the VIF-AGC charges/discharges the AGC capacitor to generate a control voltage for setting the gain of VIF amplifier U4460BG-D and tuner in order to keep the video output signal at a constant level. Therefore, the sync. level of the demodulated video signal is the criterion for a fast charge/discharge of the AGC capacitor.The control voltage (AGC voltage at Pin 7) is transferred to an internal control signal and fed to the tuner AGC to generate the tuner AGC current at Pin 12 (open collector output). The U4460BG-D take over point of the tuner AGC can be adjusted at Pin 11 by a potentiometer or an external do voltage (from interface circuit or microprocessor).

The video IF signal, which is applied from the gain controlled IF amplifier, is multiplied with the inphase component of the VCO signal. The video demodulator U4460BG-D is designed for low distortion and large bandwidth. The demodulator output signal of U4460BG-D passes an integrated low pass filter for attenuation of the residual vision carrier and is fed to the video amplifier. The video amplifier is realized by an operational amplifier with internal feedback and 8 MHz bandwidth (-3 dB). The video signal of U4460BG-D is fed to VIF-AGC and to the video output buffer. This amplifier, with a 6 dB gain, offers easy adaption of the sound trap. For nominal video IF modulation, the video output signal at Pin 13 is 2 V (peak-to-peak value).