MAX2114

DBS Direct Downconverter

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Overview

Complete Low-Cost Solution for DBS Direct Downconversion
High Level of Integration Minimizes Component Count
1MBaud to 45MBaud Operation
Selectable LO Buffer
+5V Single-Supply Operation
925MHz to 2175MHz Input Frequency Range
On-Chip Quadrature Generator, Dual-Modulus Prescaler (/32, /33)
On-Chip Crystal Oscillator Amplifier
PLL Phase Detector with Gain-Controlled Charge Pump
Input Levels: -25dBm to -68dBm per Carrier
Over 50dB Gain Control Range
Noise Figure = 10.6dB; IIP3 = +10.7dBm (at 1550MHz)
Automatic Baseband Offset Correction

The MAX2114 low-cost, direct-conversion tuner is designed for use in digital direct-broadcast satellite (DBS) television set-top box units. Its direct-conversion architecture reduces system cost compared to devices with IF-based architectures. The MAX2114 directly tunes L-band signals to baseband using a broadband I/Q downconverter. The operating frequency range spans 925MHz to 2175MHz.

The MAX2114 includes a low-noise amplifier (LNA) with gain control, I and Q downconverting mixers, lowpass filters with gain and frequency control, a local oscillator (LO) buffer with a 90° quadrature network, and a charge-pump-based phase-locked loop (PLL) for frequency control. The MAX2114 has an on-chip LO, requiring only an external varactor-tuned LC tank for operation. The LO's output drives the internal quadrature generator and has a buffer amplifier to drive off-chip circuitry. The MAX2114 comes in a 44-pin QFN package with exposed paddle (EP).

Applications