Direct-Conversion to Low-IF Tuner for Digital Audio Broadcast

The MAX2172 direct-conversion to low-IF tuner is designed for digital audio broadcast (DAB) and terrestrial digital multimedia broadcast (T-DMB) applications, covering an input frequency range of 168MHz to 240MHz (VHF-III), 1452MHz to 1492MHz (L-band), and also 87MHz to 108MHz (FM). The MAX2172 achieves a high level of component integration, allowing lowpower, tuner-on-board designs. The direct-conversion to low-IF architecture eliminates the need for an IF-SAW filter while providing a balanced 2.048MHz center frequency baseband output to the demodulator.

The MAX2172 provides a buffered reference clock at the crystal frequency.

A sigma-delta fractional-N synthesizer is incorporated to optimize both close-in and wideband phase noise performances for OFDM applications where sensitivity to both 1kHz phase noise and wideband phase noise related to strong adjacents can be a problem.

The MAX2172 is available in a 40-pin thin QFN package (6mm x 6mm) with an exposed pad. Electrical performance is guaranteed over the extended -40°C to +85°C temperature range.

Applications

* Fixed and Mobile Digital Audio Broadcast (DAB, DAB+) with FM * Terrestrial Digital Multimedia Broadcast (T-DMB) with FM

* +2.7V to +3.5V Supply Voltage Range

* Low-IF Output Eliminates IF-Saw Filter

* Integrated FM/VHF-III Bandpass Filter

* Integrated Low-IF Bandpass Filter

* Sigma-Delta Fractional-N Synthesizer

* +45dBc ACPR (N±1)

* 2.9dB Typical Noise Figure for VHF-III (Includes On-Chip Tracking Filter)

* 3.1dB Typical Noise Figure for L-Band

* VHF-III Sensitivity of -101dBm

* L-Band Sensitivity of -101dBm

* Baseband Overload Detector Controls RF AGC

* Fast Channel Scan RSSI 5-Bit Output

* FM (S+N)/N = 26dB at -111dBm

* Small 6mm x 6mm Thin QFN Package