NXP Semiconductors CX24109-11Z,557

Overview

CX24109-11Z,557 from NXP Semiconductors is a highly integrated digital satellite tuner IC implementing zero-IF direct down-conversion architecture for L-band (950–2150 MHz) RF input. It delivers I/Q baseband outputs, integrates LNA, VCO, synthesizer, and programmable VGA/VCA stages, and operates from a single +5 V supply. It targets DVB/DSS-compliant satellite set-top boxes requiring high dynamic range and low-noise front-end performance.

For engineers reviewing the CX24109-11Z,557 datasheet, CX24109-11Z,557 pinout, CX24109-11Z,557 application, or CX24109-11Z,557 equivalent, key selection criteria include its 80 dB AGC range, 48-pin eTQFP package, 10.111 MHz crystal reference interface, serial programming control, and compatibility with the CX24121 QPSK demodulator/FEC IC in broadband satellite front-end designs.

Technical Context

The CX24109-11Z,557 implements a fully integrated PLL-based local oscillator with eight overlapping VCO bands covering 2200–4400 MHz, programmable ÷2/÷4 dividers enabling continuous 950–2150 MHz tuning, and a 10.111 MHz crystal-referenced synthesizer with selectable reference dividers (÷10/÷20/÷40). Its zero-IF signal path includes RF variable gain control (VCA), quadrature downconversion, dual-channel VGA1/VGA2, and tunable low-pass filters controlled via FILTUNE voltage.

AGC is implemented as an analog feedback loop driven by external demodulator voltage (0–3 V), controlling both RF attenuation and baseband amplification across 80 dB total range. The three-wire CMOS serial interface (CLK/DATA/EN) supports 21-bit programming of band select, VGA/VCA offsets/slopes, PLL dividers, charge pump polarity/current, and reference divider settings at up to 1 MHz clock rate.

Key Specifications

Pinout & Package

Package: 48-pin enhanced Thin Quad Flat Package (eTQFP), 7 mm × 7 mm, 0.5 mm pitch, thermally enhanced with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital satellite tuner applications.

Compared with STV0297D and MT2060, the CX24109-11Z,557 offers superior integration (on-chip VCO, reference clock output, FILTUNE-controlled filters), tighter AGC coordination with demodulators, and optimized support for the CX24121 chipset-reducing total front-end component count and improving time-to-market for DVB-S STB designs.

Availability

CX24109-11Z,557 is available at Aetrix Electronics and suitable for DBS set-top boxes, commercial satellite receivers, digital VCRs, and satellite data terminals requiring stable component supply and long-term lifecycle support.

Supply support for CX24109-11Z,557 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and consumer electronics markets.

The CX24109-11Z,557 belongs to NXP's satellite communications product line, designed specifically for high-volume, cost-sensitive digital satellite receiver front-ends requiring zero-IF integration, low power consumption, and DVB/DSS compliance.

FAQ

What is the operating RF frequency range supported by the CX24109-11Z,557?

The CX24109-11Z,557 supports an RF input frequency range of 950 MHz to 2150 MHz, covering the full L-band spectrum used by DBS and DSS satellite services. This range is achieved through internal VCO banks and programmable ÷2/÷4 dividers, enabling continuous tuning without external switching. The CX24109-11Z,557 maintains specified noise figure and gain flatness across this entire band under standard operating conditions.

Does the CX24109-11Z,557 require an external crystal, and what frequency is needed?

Yes, the CX24109-11Z,557 requires an external 10.111 MHz fundamental-mode series-resonant crystal connected between XTAL1 and XTAL2 pins. This crystal serves as the reference for the internal PLL synthesizer and also feeds the CLKREFOUT pin, which provides a buffered 10.111 MHz clock to companion demodulators like the CX24121. The CX24109-11Z,557 does not support alternative reference frequencies or external clock injection.

How is AGC implemented in the CX24109-11Z,557, and what is its total range?

The CX24109-11Z,557 implements analog AGC using a single external voltage applied to the AGC pin (pin 37), which controls both the RF variable attenuator (VCA) and two baseband variable-gain amplifiers (VGA1/VGA2). This coordinated control achieves a total AGC range of 80 dB. The CX24109-11Z,557 supports programmable slope and offset adjustments for each stage via its serial interface to optimize loop behavior across symbol rates from 1 to 45 MSps.

What package type and pin count does the CX24109-11Z,557 use?

The CX24109-11Z,557 uses a 48-pin enhanced Thin Quad Flat Package (eTQFP) with 7 mm × 7 mm body size and 0.5 mm lead pitch. It features an exposed thermal pad on the underside for improved heat dissipation and includes 10 VCC and 18 GND pins distributed across the perimeter to minimize supply noise and ensure stable RF performance. The CX24109-11Z,557 pinout is documented in Figure 1 and Table 1 of its NXP datasheet.

Can the CX24109-11Z,557 be used without the CX24121 demodulator?

Yes, the CX24109-11Z,557 can be used with other QPSK demodulators or custom baseband processors, as it provides standard differential I/Q outputs (IOUTP/IOUTN, QOUTP/QOUTN) and supports independent AGC, FILTUNE, and LD signaling. However, its default programming values, reference clock output (CLKREFOUT), and recommended application schematics are optimized for interoperability with the CX24121. Using alternate demodulators may require reprogramming VGA/VCA parameters and verifying timing alignment. The CX24109-11Z,557 remains fully functional outside the CX24121 ecosystem.