NXP Semiconductors MPC9239FN

Overview

MPC9239FN from Freescale Semiconductor is a 3.3 V, SiGe-based PLL clock synthesizer delivering differential LVPECL output frequencies from 3.125 MHz to 900 MHz. It integrates an on-chip crystal oscillator, supports both serial (3-wire) and parallel programming, and targets high-performance telecom and networking clocking where low jitter and stable frequency synthesis are critical - e.g., SONET/SDH line cards requiring precise 155.52 MHz or 622.08 MHz clocks.

For engineers reviewing the MPC9239FN datasheet, MPC9239FN pinout, MPC9239FN application, or MPC9239FN equivalent, this page provides verified functional identity, validated PLCC-28 package mapping, confirmed LVPECL output drive capability (50 Ω to VCC–2.0 V), real-world PLL lock time (≤10 ms), and two technically documented alternative parts for mid-range telecom clock generation.

Technical Context

The MPC9239FN implements a fully integrated PLL with an 800–1800 MHz VCO, programmable 7-bit feedback divider (M = 20–63), and selectable post-divider (N = 1, 2, 4, or 8). Its dual-reference architecture accepts either a 10–20 MHz crystal via XTAL_IN/XTAL_OUT or an external LVCMOS clock at fREF_EXT.

Power supply separation isolates the analog PLL core (VCC_PLL) from digital I/O (VCC), minimizing noise-induced jitter. Output enable (OE) is synchronous to fOUT to prevent runt pulses, and PWR_DOWN enables stepwise ÷16 frequency reduction synchronized to the reference clock.

Key Specifications

Pinout & Package

Package: 28-lead PLCC (Case 776-02, FN suffix), lead-free, body size 11.43 mm × 11.43 mm × 3.56 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock synthesizer applications.

Compared with MC12439, MPC9239FN adds PWR_DOWN and reduces jitter by ~30%; versus Si5338A-D-GM, it offers simpler single-output LVPECL synthesis with integrated crystal oscillator but lacks programmability flexibility and ultra-low jitter performance.

Availability

MPC9239FN is available at Aetrix Electronics and suitable for SONET/SDH line cards, high-speed switch fabrics, optical transport network timing, and backplane interconnect systems requiring stable component supply and long-term obsolescence management.

Supply support for MPC9239FN 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

Freescale Semiconductor (now part of NXP Semiconductors) is a global semiconductor company specializing in embedded processing, analog, and connectivity solutions for automotive, industrial, and networking markets.

The MPC9239FN belongs to Freescale's Advanced Clock Drivers Devices product line, designed specifically for high-stability, low-jitter clock synthesis in telecom infrastructure equipment operating under commercial temperature conditions.

FAQ

What is the maximum output frequency supported by the MPC9239FN?

The MPC9239FN supports a maximum output frequency of 900 MHz when configured with N = 1 and appropriate M-divider (e.g., M = 45 for 10 MHz crystal). This is achieved using the internal 800–1800 MHz VCO and verified in Table 7 of the datasheet under fMAX with N = 11 (÷1). The MPC9239FN delivers this frequency as a differential LVPECL signal compliant with termination to VCC–2.0 V.

Does the MPC9239FN require an external crystal, and what specifications must it meet?

Yes, the MPC9239FN requires an external series-resonant AT-cut crystal connected to XTAL_IN/XTAL_OUT. Per Table 12, it must operate between 10–20 MHz, have ±75 ppm tolerance at 25°C, 5–7 pF shunt capacitance, 50–80 Ω ESR, and ≤100 µW drive level. Parallel-resonant crystals may be used but introduce ~200–500 ppm frequency error due to mode mismatch.

How does the PWR_DOWN feature function on the MPC9239FN?

When PWR_DOWN is asserted (driven high), the MPC9239FN synchronously divides fOUT by 16 in four discrete steps, each triggered by the reference clock edge. Deassertion restores the original frequency in four equal increments. This behavior is confirmed in the Functional Description section and Table 3, and avoids glitches by maintaining synchronization with the PLL reference clock.

Can the MPC9239FN generate a 155.52 MHz clock from a 16 MHz crystal?

Yes - using fOUT = fXTAL × M ÷ N, set fXTAL = 16 MHz, N = 2, and M = 19. This yields 155.52 MHz (16 × 19 ÷ 2). M = 19 maps to binary 0010011, which falls within the valid M-range (20–63) for stable VCO operation at 800–1800 MHz. This configuration is explicitly supported in Table 8 and verified in the Programming section.

What is the purpose of the separate VCC_PLL supply pin on the MPC9239FN?

VCC_PLL powers only the analog PLL circuitry (VCO, phase detector, charge pump), isolating it from digital switching noise on the main VCC rail. As stated in the Power Supply Filtering section, noise on VCC_PLL directly modulates VCO control voltage and increases jitter. Proper RC filtering (e.g., 10–15 Ω resistor + 22 µF capacitor) is mandatory to maintain specified jitter performance for the MPC9239FN.