TDA8051

This TDA8051 is a monolithic bipolar IC intended for Quadrature Phase Shift Key (QPSK) demodulation. It includes:

   · Low noise RF and gain controlled amplifier
   · Two matched mixers
   · Symmetrical Voltage Controlled Oscillator (VCO) with 0 to 90° signal generator whose frequency is controlled
       by an integrated Phase Lock Loop (PLL) circuit.
   · Two matched amplifiers for output base-band active filtering and output buffers

The gain control of TDA8051 is produced by output level detection compared with an external pre-fixed reference. The PLL consists of:

   · Divide by four preamplifier
   · 12-bit programmable main divider
   · Crystal oscillator with 8-bit programmable reference divider
   · Phase/frequency detector combined with charge pump to drive tuning amplifier
   · 30 V output