QPSK satellite tuner with integrated high-sensitivity LNA and loop-through

TDA20143 is a general-purpose QPSK satellite tuner that addresses the stringent requirements of both operator and Free To Air (FTA) applications. It includes an integrated high-sensitivity Low Noise Amplifier (LNA) and a large dynamic range. The device also includes a built-in RF Loop-Through (LPT).

To address FTA applications, the TDA20143’s built-in high-sensitivity LNA provides Noise Figure (NF) without the need for any external amplification. The TDA20143's allows it to achieve this NF for low-power signals without sacrificing linearity (IIP3, IIP2) when total power is high. This characteristic makes the TDA20143 ideal for operator applications. The LNA also includes multiple settings to allow power reduction when higher linearity is not required.

The tuner employs a fractional PLL that provides good phase noise while enabling fine step size without adversely affecting lock time. Additional features include a built-in auto-tuning function, a single-ended RF input and a buffered version of the crystal clock with optional dividers that is made available to drive companion ICs.

The device’s flexible LPT includes a buffer and an attenuator with four settings. This allows flexibility when connected in cascade with a second satellite tuner. Good reverse isolation assures that interaction between the two tuners connected via the LPT path does not affect the desired signal.