NXP Semiconductors MC88LV915TFNR2

Overview

The MC88LV915TFNR2 from Motorola is a low-skew CMOS PLL clock driver designed for synchronous clock distribution in high-performance PC and workstation systems. It locks five Q outputs (Q0–Q4) to a reference clock with <500 ps output-to-output skew, provides 2X_Q (up to 100 MHz) and Q/2 outputs, and supports frequency multiplication (2×), unity (1×), and division (÷2) modes via FREQ_SEL control.

For engineers reviewing the MC88LV915TFNR2 datasheet, MC88LV915TFNR2 pinout, MC88LV915TFNR2 application, or MC88LV915TFNR2 equivalent, key selection criteria include guaranteed 500 ps rising-edge skew across Q0–Q4, 3.3 V ±0.3 V supply operation, 28-lead PLCC package compatibility, and support for board-level test modes via PLL_EN and OE/RST pins.

Technical Context

The MC88LV915TFNR2 implements a phase-locked loop with internal VCO optimized for 20–100 MHz operation, enabling precise synchronization of multiple system components to a single reference clock. Its feedback path includes programmable divide-by-1 or divide-by-2 (via FREQ_SEL), allowing VCO tuning across input frequencies from 5 MHz to 50 MHz while maintaining optimal performance.

It features dual SYNC inputs - one for normal PLL operation and a second for low-frequency board testing - and integrates a lock indicator (LOCK) that asserts high within 10 ms of stable phase/frequency lock. All outputs (2X_Q, Q0–Q4, Q5, Q/2) support ±36 mA CMOS/TTL drive with 50 Ω transmission line switching capability.

Key Specifications

Pinout & Package

MC88LV915TFNR2 is housed in a 28-lead plastic leaded chip carrier (PLCC), case 776–02 (FN suffix), with leads arranged in a square perimeter and body dimensions per Motorola outline drawing D.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICS853S01I and PI6C20400, the MC88LV915TFNR2 uniquely combines programmable PLL feedback (FREQ_SEL), five low-skew Q outputs, an inverted Q5, and dual SYNC inputs in a single 3.3 V CMOS device - making it optimal for upgradeable, test-friendly PC and workstation clock trees where flexibility and board-level debug capability are critical.

Availability

MC88LV915TFNR2 is available at Aetrix Electronics and suitable for desktop PC motherboard design, workstation multi-processor synchronization, and embedded industrial controller timing requiring stable component supply and long-term obsolescence management.

Supply support for MC88LV915TFNR2 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

Motorola Semiconductor (now part of NXP Semiconductors) was a pioneer in high-performance clock distribution ICs, emphasizing low-jitter, low-skew timing solutions for computing infrastructure.

The MC88LV915TFNR2 belongs to Motorola's low-skew CMOS PLL clock driver family, engineered specifically for synchronous clock distribution in high-end PCs and workstations where deterministic phase alignment and board-level testability are mandatory.

FAQ

What is the maximum guaranteed operating frequency of the 2X_Q output on the MC88LV915TFNR2?

The MC88LV915TFNR2 guarantees a maximum operating frequency of 100 MHz for the 2X_Q output under recommended conditions (TA = 0°C to +70°C, VCC = 3.3 V ±0.3 V, 50 Ω load terminated to VCC/2). This specification is validated with the device in phase-locked condition and reflects the upper limit for stable, low-jitter operation across production units.

How does the FREQ_SEL pin affect the PLL behavior of the MC88LV915TFNR2?

The FREQ_SEL pin on the MC88LV915TFNR2 selects the feedback divider ratio in the PLL: logic-high configures divide-by-1, while logic-low configures divide-by-2. This allows the internal VCO to operate within its optimal 20–100 MHz range even when driven by low-frequency reference clocks (e.g., 25 MHz input yields 50 MHz VCO with FREQ_SEL low), preserving jitter performance and lock stability in the MC88LV915TFNR2.

Can the MC88LV915TFNR2 support board-level functional testing without modifying the clock tree?

Yes - the MC88LV915TFNR2 supports dedicated board-level testing via two mechanisms: pulling PLL_EN low bypasses the VCO and routes SYNC directly to outputs, enabling low-frequency validation; pulling OE/RST low places all clock outputs (2X_Q, Q0–Q4, Q5, Q/2) into high-impedance state, eliminating signal contention during boundary-scan or logic analyzer probing - both features are fully integrated into the MC88LV915TFNR2 design.

What is the guaranteed output-to-output skew specification for Q0–Q4 on the MC88LV915TFNR2?

The MC88LV915TFNR2 guarantees ≤500 ps output-to-output skew between the rising edges of Q0–Q4 under specified conditions (TA = 0°C to +70°C, VCC = 3.3 V ±0.3 V, matched 50 Ω loads terminated to VCC/2). This skew value is measured across production units and represents the maximum window between earliest and latest rising edge crossings at VCC/2, ensuring timing predictability in tightly synchronized systems using the MC88LV915TFNR2.

Does the MC88LV915TFNR2 provide any built-in indication of PLL lock status?

Yes - the MC88LV915TFNR2 includes a dedicated LOCK output pin that transitions high when the PLL achieves and maintains steady-state phase and frequency lock. The LOCK signal asserts no later than 10 ms after a valid SYNC input is detected and full 3.3 V supply is established, and goes low if lock is lost or PLL_EN is pulled low - providing deterministic feedback for system boot sequencing and fault detection in designs using the MC88LV915TFNR2.