NXP Semiconductors CX24118A-12Z,557

Overview

CX24118A-12Z,557 from NXP Semiconductors is a single-chip, direct-conversion digital satellite tuner for DVB-S2 and 8PSK systems. It operates across 925–2175 MHz RF input, delivers 10 dB typical noise figure, supports 1–45 MSps symbol rates, and integrates zero-IF architecture with auto-tuning to eliminate software calibration-enabling compact set-top box receivers.

For engineers reviewing the CX24118A-12Z,557 datasheet, CX24118A-12Z,557 pinout, CX24118A-12Z,557 application, or CX24118A-12Z,557 equivalent, this page provides verified functional context, validated pin roles, confirmed RF/baseband performance boundaries, and real-world implementation constraints including crystal oscillator biasing, AGC interface behavior, and fractional PLL register programming requirements.

Technical Context

The CX24118A-12Z,557 implements a zero-IF architecture with integrated quadrature downconversion, dual-stage variable-gain baseband amplification (VGA1/VGA2), and DC offset cancellation on both I/Q paths. Its fractional-N PLL uses an 18-bit sigma-delta modulator and 9-bit integer divider to achieve fine frequency resolution without spurious tones.

It features six on-die VCOs (12 virtual bands) covering 925–2175 MHz, automatically selected via preload registers (0x14–0x17); charge pump current is dynamically adjusted across four tuning voltage ranges to optimize integrated phase noise. The crystal oscillator supports 40 MHz or 40.444 MHz third-overtone crystals with external LC network (C1=22 pF, C2=56 pF, C3=1 nF, L1=390 nH).

Key Specifications

Pinout & Package

Package: 36-pin QFN, 6 mm × 6 mm, lead-free and RoHS compliant, with exposed thermal paddle connected to GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STV0900 and MT8222, the CX24118A-12Z,557 offers superior RF integration (zero-IF, no balun), wider symbol rate range (up to 45 MSps), and flexible I²C-controlled gain/filter tuning-making it optimal for next-generation DVB-S2 receivers requiring layout efficiency and signal fidelity.

Availability

CX24118A-12Z,557 is available at Aetrix Electronics and suitable for 8PSK/DVB-S2 set-top boxes, commercial PVR receivers, and advanced modulation broadcast terminals requiring stable component supply across extended production lifecycles.

Supply support for CX24118A-12Z,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 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,557 belongs to NXP's satellite tuner product line, engineered specifically for high-volume digital video receivers demanding low implementation loss, excellent phase noise, and seamless DVB-S2/8PSK compatibility.

FAQ

What is the required crystal configuration for CX24118A-12Z,557?

The CX24118A-12Z,557 requires a 40 MHz or 40.444 MHz third-overtone crystal with parallel-resonant mode and 18 pF load capacitance. External components must include C1=22 pF, C2=56 pF, C3=1 nF, and L1=390 nH. For 45 MSps DVB-S2 operation, the 40.444 MHz crystal is mandatory-using the 40 MHz variant limits symbol rate to ≤44 MSps. The CX24118A-12Z,557 crystal oscillator section is configured via XSEL (pin 35) and XTAL_BIAS (pin 6) per datasheet Section 2.5.

Does CX24118A-12Z,557 require external calibration during startup?

No, the CX24118A-12Z,557 incorporates an auto-tuning system that eliminates software calibration. During initialization, registers 0x14–0x17 are preloaded with VCO band selection values, and the automatic tuning engine selects the optimal VCO and band based on target frequency-achieving lock without iterative measurement. This capability is confirmed in Section 2.6 of the CX24118A-12Z,557 datasheet and reduces boot time in production receivers.

How does the AGC interface function on CX24118A-12Z,557?

The AGC pin (Pin 22) on CX24118A-12Z,557 is an analog input (10 kΩ // 20 pF) that accepts a voltage from the downstream demodulator to control gain across three stages: RF attenuator, VGA1, and VGA2. It enables coordinated gain management across the signal chain, delivering 90 dB total dynamic range. The CX24118A-12Z,557 interprets AGC voltage levels per Table 2 and Table 3 in the datasheet to select optimized gain settings for high- or low-input-power scenarios.

Can CX24118A-12Z,557 operate without a balun?

Yes, the CX24118A-12Z,557 accepts differential RF input directly via RF_INP (Pin 25) and RF_INN (Pin 26), eliminating the need for an external balun. Its integrated low-noise amplifier and quadrature downconverter are designed for balanced operation, reducing BOM cost and improving amplitude/phase matching versus single-ended architectures. This is explicitly stated in the General Description and Features sections of the CX24118A-12Z,557 product data sheet.

What are the power supply requirements for CX24118A-12Z,557?

The CX24118A-12Z,557 requires seven dedicated 3.3 V supplies: VCC_VCO (Pin 2), VCC_CP (Pin 4), VCC_XTAL (Pin 7), VCC_DIG (Pin 11), VCC1_BB (Pin 23), VCC2_BB (Pin 21), VCC1_RF (Pin 24), VCC2_RF (Pin 31), and VCC_PS (Pin 36). Each rail serves an isolated circuit block to minimize noise coupling-especially critical for VCO and RF sections. Decoupling capacitors (100 nF + 10 nF) must be placed within 2 mm of each VCC pin per Section 5.2.2 of the CX24118A-12Z,557 datasheet.