NXP Semiconductors CX24118A-12Z,518

Overview

CX24118A-12Z,518 from NXP Semiconductors is a single-chip direct-conversion satellite tuner IC for DVB-S2 and 8PSK systems, operating across 925–2175 MHz RF input, supporting symbol rates up to 45 MSps, with 10 dB typical noise figure and integrated fractional PLL synthesizer. It serves as the RF-to-baseband front-end in set-top boxes and digital video receivers.

For engineers reviewing the CX24118A-12Z,518 datasheet, CX24118A-12Z,518 pinout, CX24118A-12Z,518 application, or CX24118A-12Z,518 equivalent, key selection criteria include zero-IF architecture eliminating image-reject filters, auto-tuning eliminating software calibration, differential I/Q baseband outputs (1 kΩ // 10 pF), and 36-pin QFN package compatibility with high-density satellite receiver layouts.

Technical Context

The CX24118A-12Z,518 implements a zero-IF architecture with quadrature downconversion, dual variable-bandwidth baseband filters (2–100 MHz selectable), and DC offset cancellation on both I and Q paths. Its integrated fractional-N PLL uses an 18-bit sigma-delta modulator and 9-bit integer divider to achieve fine frequency resolution without degrading lock time.

It features six on-die VCOs (12 virtual bands) covering 925–2175 MHz, automatically selected via preload registers; charge pump current is dynamically adjusted across four tuning voltage ranges to optimize phase noise. The crystal oscillator supports 40 MHz or 40.444 MHz third-overtone crystals with external LC network for overtone suppression.

Key Specifications

Pinout & Package

Package: 36-pin QFN (6 mm × 6 mm, exposed paddle grounded), lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STV0900 and MT2060, the CX24118A-12Z,518 delivers superior integration (no balun, no external VCO), faster channel switching via auto-tuning, and full 45 MSps DVB-S2 support-making it optimal for new high-efficiency satellite receiver designs where BOM reduction and time-to-market are critical.

Availability

CX24118A-12Z,518 is available at Aetrix Electronics and suitable for 8PSK set-top boxes, DVB-S2 professional receivers, and commercial PVR systems requiring stable component supply, long-term lifecycle support, and consistent electrical performance across production batches.

Supply support for CX24118A-12Z,518 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 leader focused on secure connectivity solutions for automotive, industrial, and consumer applications, with deep expertise in RF and mixed-signal IC design.

The CX24118A-12Z,518 belongs to NXP's advanced satellite tuner product line, engineered specifically for high-volume DVB-S2 and 8PSK receiver platforms demanding low power, minimal external components, and rapid channel acquisition.

FAQ

What is the primary function of the CX24118A-12Z,518 in a satellite receiver system?

The CX24118A-12Z,518 functions as a direct-conversion RF-to-baseband satellite tuner IC, accepting L-band signals (925–2175 MHz) from an LNB and delivering differential I/Q baseband outputs to a DVB demodulator. Its zero-IF architecture, integrated fractional-N PLL, and auto-tuning system make the CX24118A-12Z,518 ideal for compact, high-performance DVB-S2 and 8PSK receivers without external baluns or calibration routines.

Does the CX24118A-12Z,518 require an external balun for RF input?

No, the CX24118A-12Z,518 does not require an external balun. It accepts differential RF input directly via RF_INP and RF_INN pins, and its internal architecture eliminates the need for image-reject filtering or balun components-reducing BOM cost and PCB area. This capability is explicitly confirmed in the NXP datasheet General Description section.

What crystal frequency options are supported by the CX24118A-12Z,518?

The CX24118A-12Z,518 supports two third-overtone crystal frequencies: 40.000 MHz for standard DVB-S2 operation and 40.444 MHz specifically to enable 44–45 MSps symbol rates with the CX24116 DVB-S2 demodulator. Both require external LC network components (C1=22 pF, C2=56 pF, C3=1 nF, L1=390 nH) as specified in the official datasheet.

How does the auto-tuning system in the CX24118A-12Z,518 simplify system design?

The CX24118A-12Z,518 auto-tuning system eliminates software calibration during initialization and channel changes by preloading VCO band selection values into registers (0x14–0x17) and dynamically selecting the optimal VCO based on target frequency. This reduces firmware complexity, accelerates channel acquisition, and ensures consistent performance across temperature and voltage variations-verified in Section 2.6 of the NXP datasheet.

What is the role of the AGC pin on the CX24118A-12Z,518?

The AGC pin (Pin 22) on the CX24118A-12Z,518 is an analog input that receives a control voltage from the downstream demodulator to adjust gain across multiple stages: RF VCA, VGA1, VGA2, and final amplifier-delivering 90 dB total dynamic range. Its 10 kΩ // 20 pF input impedance is designed for direct connection to standard DVB demodulator AGC outputs without buffering.