Complete SDARS Receiver

The MAX2140 complete receiver is designed for satellite digital audio radio services (SDARS). The device includes a fully monolithic VCO and only needs a SAW at the IF and a crystal to generate the reference frequency.

To form a complete SDARS radio, the MAX2140 requires only a low-noise amplifier (LNA), which can be controlled by a baseband controller. The small number of external components needed makes the MAX2140-based platform the lowest cost and the smallest solution for SDARS.

The receiver includes a self-contained RF AGC loop and baseband-controlled IF AGC loop, effectively providing a total dynamic range of over 92dB.

Channel selectivity is ensured by the SAW filter and by on-chip monolithic lowpass filters.

The fractional-N PLL allows a very small frequency step, making possible the implementation of an AFC loop. Additionally, the reference is provided by an external XTAL and on-chip oscillator. A reference buffer output is also provided.

A 2-wire interface (I²C bus compatible) programs the circuit for a wide variety of conditions, providing features such as:

* Programmable gains

* Lowpass filters tuning

* Individual functional block shutdown

The MAX2140 minimizes the requirement on the baseband controller. No compensation or calibration procedures are required. The device is available in a 7mm x 7mm 44-pin thin QFN package.Applications

* 2.4GHz ISM Radios * Satellite Digital Audio Radio Services (SDARS)

* Integrated Receiver, Requires Only One SAW Filter

* Self-Contained RF AGC Loop

* Differential I/Q Interface

* Complete Integrated Frequency Generation

* Bias Supply for External LNAs

* Overcurrent Protection

* Low-Power Standby Mode

* Very Small 44-Pin Thin QFN Package