NXP Semiconductors MPC9608AC

Overview

MPC9608AC from NXP Semiconductors (formerly Freescale) is a 3.3 V, 1:10 LVCMOS zero-delay clock buffer with PLL-based phase alignment, designed for high-performance clock tree distribution in networking and telecom systems. It delivers 12.5–200 MHz input frequency support, <150 ps bank-to-bank output skew, and dual 5-output banks (QA0–QA4, QB0–QB4) with selectable ÷2 division on Bank B.

For engineers reviewing the MPC9608AC datasheet, MPC9608AC pinout, MPC9608AC application, or MPC9608AC equivalent, key selection criteria include its zero-delay PLL architecture, synchronous CLK_STOP control, tristate OE capability, and Pb-free 32-lead LQFP package optimized for low-jitter, multi-processor clock fanout.

Technical Context

The MPC9608AC uses an internal PLL with external feedback (QFB → FB_IN) to achieve near-zero insertion delay by aligning output edges precisely to the CCLK reference edge. Its dual-bank architecture supports independent frequency scaling: Bank A outputs replicate CCLK, while Bank B can be configured via BSEL to either mirror Bank A or divide by two - both remaining fully synchronized to the reference.

It features separate analog (VCCA) and digital (VCC) power domains, requiring an external RC filter on VCCA to suppress 100 kHz–20 MHz noise and maintain ≤125 ps RMS I/O phase jitter. Control signals CLK_STOP and OE operate independently - CLK_STOP stops outputs synchronously in logic-low state, while OE forces high-impedance without affecting QFB or PLL lock.

Key Specifications

Pinout & Package

Package: 32-lead Pb-free LQFP (7×7 mm², Case 873A-03), RoHS-compliant, with exposed thermal pad (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT5V9885BGI and ICS853S112AGI, the MPC9608AC uniquely combines 10-output fanout, programmable bank division, and externally adjustable zero-delay via QFB feedback - making it optimal for complex, multi-frequency clock trees requiring precise inter-bank phase alignment.

Availability

MPC9608AC is available at Aetrix Electronics and suitable for networking switch fabric, telecom line card timing, and multi-core processor clock tree applications requiring stable component supply, long-term lifecycle support, and guaranteed Pb-free compliance.

Supply support for MPC9608AC 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 acquired Freescale in 2015 and maintains full technical and supply chain continuity for legacy Freescale clock products including the MPC9608AC.

The MPC9608AC belongs to NXP's Advanced Clock Drivers portfolio, engineered specifically for low-skew, zero-delay clock distribution in high-speed communications infrastructure and industrial control systems.

FAQ

What is the function of the QFB and FB_IN pins on the MPC9608AC?

The QFB pin outputs a phase-aligned copy of the CCLK reference clock, which must be connected directly to the FB_IN pin to close the PLL feedback loop. This external feedback path is essential for zero-delay operation - without it, the MPC9608AC cannot lock the output phase to the input reference, and propagation delay reverts to standard buffer behavior. The MPC9608AC datasheet specifies strict trace-length matching guidelines for the QFB→FB_IN connection to minimize skew-induced jitter.

How does the BSEL pin affect clock output frequencies on the MPC9608AC?

The BSEL pin selects whether Bank B outputs (QB0–QB4) run at the same frequency as Bank A (f_REF) or half that frequency (f_REF/2). When BSEL = 0, QB outputs match QA outputs; when BSEL = 1, they divide by two - e.g., a 100 MHz CCLK yields 100 MHz QA outputs and 50 MHz QB outputs. This configuration is static per power-up and does not affect synchronization: both banks remain phase-aligned to CCLK regardless of division ratio.

Can the MPC9608AC operate without the external RC filter on VCCA?

No - the MPC9608AC requires an external RC filter (9–10 Ω resistor + 33–100 nF capacitor) on the VCCA pin to meet its specified 125 ps RMS phase jitter. Without this filter, noise coupling into the PLL's analog supply degrades jitter performance significantly, especially in the 100 kHz–20 MHz band. The MPC9608AC datasheet Figure 3 provides the exact recommended values and layout guidance to ensure compliance with AC timing specifications.

What is the difference between CLK_STOP and OE control on the MPC9608AC?

CLK_STOP synchronously gates all QA/QB outputs to logic-low state only - it preserves duty cycle integrity and requires the output to already be low before stopping. OE places all QA/QB outputs in high-impedance (tristate), independent of CLK_STOP state or output level. Critically, neither signal affects the QFB output or PLL lock status, allowing downstream clocks to be disabled without losing synchronization - a key feature for the MPC9608AC in hot-plug and power-gating scenarios.

Is the MPC9608AC pin-compatible with other members of the MPC96xx family?

The MPC9608AC shares the same 32-lead LQFP package and core pinout (CCLK, FB_IN, QFB, QA0–QA4, QB0–QB4, BSEL, CLK_STOP, OE, VCCA, VCC, GND) with MPC9604AC and MPC9610AC, but differs in output count and division capability. While pin locations match, the MPC9608AC's dual 5-output bank structure and BSEL-controlled ÷2 function are not replicated identically in other variants - direct substitution requires verification of functional mapping and timing constraints in the target design.