NXP Semiconductors MPC961CFA

Overview

MPC961CFA from Freescale Semiconductor (formerly Motorola) is a 2.5V/3.3V-compatible, 1:18 PLL-based zero-delay clock buffer IC with LVCMOS inputs/outputs, 200 MHz max output frequency, ±50 ps cycle-to-cycle jitter, and 150 ps output-to-output skew. It serves as a high-precision clock distribution device in synchronous digital systems requiring tight skew control and phase alignment-e.g., high-speed memory interfaces and FPGA clock trees.

For engineers reviewing the MPC961CFA datasheet, MPC961CFA pinout, MPC961CFA application, or MPC961CFA equivalent, this page delivers verified technical context, real-world timing performance metrics, package-specific layout guidance, and validated alternative options for clock tree design and supply continuity planning.

Technical Context

The MPC961CFA integrates a fully self-contained PLL with no external loop filter required, supporting two selectable frequency ranges (50–100 MHz or 100–200 MHz) via the F_RANGE input. Its analog/digital power separation-VCCA for PLL core and VCC for I/O-enables noise isolation critical for low-jitter operation.

It implements zero-delay functionality through external feedback (FB_IN connected to QFB), aligning output edges to the reference clock edge with static phase offset bounded between –80 ps and +120 ps. All 17 outputs (Q0–Q16) are LVCMOS, while QFB provides dedicated PLL feedback output unaffected by OE assertion.

Key Specifications

Pinout & Package

The MPC961CFA is housed in a 32-lead LQFP (FA suffix, Case 873A–02), measuring 7.0 mm × 7.0 mm × 1.4 mm, with 0.8 mm lead pitch and exposed thermal pad. Requires separate RC filtering on VCCA for analog PLL stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar zero-delay clock buffer applications.

Compared with IDT5V9885BGI and ICS853S01I, the MPC961CFA offers superior scalability (17 outputs), dual-voltage support, configurable PLL bandwidth, and dedicated QFB for precise skew calibration-making it uniquely suited for complex, multi-tier clock architectures demanding traceable phase alignment.

Availability

MPC961CFA is available at Aetrix Electronics and suitable for high-speed memory interface clock distribution, FPGA/ASIC clock tree synthesis, network processor timing, and industrial control backplane synchronization requiring stable component supply and long-term lifecycle assurance.

Supply support for MPC961CFA 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) was a leading designer of high-performance timing, microcontroller, and analog ICs for communications, automotive, and industrial markets.

The MPC961CFA belongs to Freescale's TIMING SOLUTIONS product line, engineered specifically for low-skew, zero-delay clock distribution in high-speed digital systems where deterministic timing and jitter resilience are critical.

FAQ

What is the function of the QFB pin on the MPC961CFA?

The QFB pin on the MPC961CFA is a dedicated LVCMOS output that delivers the PLL feedback clock signal. It must be connected to the FB_IN input to configure the device in zero-delay mode. Unlike other outputs, QFB remains active even when the OE pin is asserted, ensuring continuous PLL lock during selective output disabling-critical for maintaining timing integrity in multi-stage clock trees.

Does the MPC961CFA require external loop filter components?

No, the MPC961CFA does not require external loop filter components for PLL operation. Its fully integrated PLL eliminates discrete capacitors or resistors in the control loop. However, an external RC filter (e.g., 270 Ω + 10 nF + 22 µF for 3.3 V) is mandatory on the VCCA pin to suppress noise in the 10 kHz–10 MHz range and maintain analog PLL stability-per Freescale Application Note DL207.

How does the F_RANGE pin affect MPC961CFA performance?

The F_RANGE pin on the MPC961CFA selects the PLL's operating frequency band: logic low (0) enables 100–200 MHz operation, while logic high (1) configures 50–100 MHz. This setting adjusts internal PLL bandwidth and charge pump gain to optimize jitter and lock time for the selected range-ensuring minimal cycle-to-cycle jitter (±15 ps RMS) and fast lock (<10 ms) across both bands.

Can the MPC961CFA drive multiple transmission lines per output?

Yes, the MPC961CFA can drive two 50 Ω series-terminated transmission lines per output due to its low output impedance (<15 Ω). This capability doubles effective fanout to 1:36. Simulations confirm only a 43 ps delay delta between single- and dual-line loading, preserving tight output-to-output skew (≤150 ps)-enabling compact, high-density clock routing without repeaters.

What is the maximum junction temperature for reliable MPC961CFA operation?

The MPC961CFA is rated for long-term reliability at a maximum die junction temperature (TJ) of 120 °C, corresponding to an MTBF of 4.2 years per Freescale AN1545. For 9.1-year MTBF, TJ must be held ≤110 °C. Thermal design must account for Rthja (55–80 K/W depending on airflow) and total power dissipation-including VCCA current (up to 5 mA) and dynamic load-especially at 200 MHz with 3.3 V supply.

Is the MPC961CFA pin-compatible with the MPC961PFA?

No, the MPC961CFA is not pin-compatible with the MPC961PFA. While both share identical 32-lead LQFP packaging and pin numbering, the MPC961PFA accepts LVPECL reference inputs (requiring different termination and biasing), whereas the MPC961CFA is LVCMOS-only. Swapping them without circuit revision risks input stage damage or PLL failure due to incompatible voltage levels and drive requirements.