Texas Instruments LMK04111SQ/NOPB

Overview

LMK04111SQ/NOPB from Texas Instruments is a precision clock jitter cleaner with cascaded PLL architecture, delivering five low-jitter LVPECL outputs up to 1080 MHz. It features dual PLLs (PLL1 for reference conditioning, PLL2 with integrated VCO), 1430–1570 MHz VCO tuning range, and supports redundant reference inputs with loss-of-signal detection for cellular basestation timing recovery.

For engineers reviewing the LMK04111SQ/NOPB datasheet, LMK04111SQ/NOPB pinout, LMK04111SQ/NOPB application, or LMK04111SQ/NOPB equivalent, key selection criteria include VCO frequency range, output format configurability (LVPECL only on this variant), PLL2 phase detector rate (up to 100 MHz), and industrial temperature operation (-40°C to +85°C).

Technical Context

The LMK04111SQ/NOPB implements a two-stage PLLatinum™ architecture: PLL1 accepts dual AC/DC-coupled reference inputs (CLKin0/CLKin1) with automatic/manual switching and loss-of-signal monitoring, while PLL2 uses an external VCXO or crystal (6–20 MHz) and integrates a 1430–1570 MHz VCO with programmable charge pump gain (100–3200 µA). Its 5-channel output distribution supports independent divider blocks and common telecom frequencies including 122.88 MHz, 156.25 MHz, and 311.04 MHz.

Each of the five differential clock outputs (CLKout0–CLKout4) is fixed as LVPECL in this variant (per Table 2), with output skew ≤40 ps between channels at 800 MHz and integrated RMS jitter of 75 fs (1.875–20 MHz) at 153.6 MHz output. The device operates from a single 3.15–3.45 V supply and includes MICROWIRE (SPI-compatible) programming interface with lock detect (LD) and global output enable (GOE) control signals.

Key Specifications

Pinout & Package

LMK04111SQ/NOPB is housed in a thermally enhanced 48-pin WQFN package (7.0 × 7.0 × 0.8 mm) with exposed die attach pad (DAP) connected to GND for optimal thermal dissipation (θJ-PAD = 5.8°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMK04110SQ/NOPB, LMK04111SQ/NOPB provides higher VCO frequency and output capability for 10G+ systems; versus LMK04131SQ/NOPB, it trades output format flexibility for superior channel count and jitter performance in pure LVPECL timing trees.

Availability

LMK04111SQ/NOPB is available at Aetrix Electronics and suitable for cellular basestation timing, optical transport network line cards, and high-speed data converter clocking requiring stable component supply across extended product lifecycles.

Supply support for LMK04111SQ/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with broad industrial and communications portfolio coverage.

The LMK041xx family was designed specifically for high-performance timing in wireless infrastructure, optical networking, and test equipment - emphasizing jitter attenuation, redundancy, and programmable PLL flexibility.

FAQ

What is the VCO tuning range of the LMK04111SQ/NOPB?

The LMK04111SQ/NOPB features an integrated VCO with a guaranteed tuning range of 1430 MHz to 1570 MHz. This range is validated across the full industrial temperature range (-40°C to +85°C) and enables direct synthesis of critical telecom frequencies including 153.6 MHz (CPRI), 156.25 MHz (10GbE), and 311.04 MHz (SONET OC-48) without external VCO components. The LMK04111SQ/NOPB uses this VCO in PLL2 to achieve ultra-low jitter multiplication.

Does the LMK04111SQ/NOPB support crystal oscillator input?

Yes, the LMK04111SQ/NOPB supports direct connection of a fundamental-mode crystal (6–20 MHz) to the OSCin/OSCin* pins. The device includes internal load capacitance and bias circuitry optimized for crystals like the Vectron VXB1 series. The EN_PLL2_REF2X bit (Register 13) can be enabled to double the crystal frequency, allowing use of lower-cost 12.288 MHz or 13.28125 MHz crystals to generate 153.6 MHz or 159.375 MHz outputs. The LMK04111SQ/NOPB does not require external oscillator modules.

How many clock outputs does the LMK04111SQ/NOPB provide, and what are their formats?

The LMK04111SQ/NOPB provides five fully differential clock outputs (CLKout0 through CLKout4), all configured exclusively as LVPECL in this specific variant. Unlike other members of the LMK041xx family, the LMK04111SQ/NOPB does not support LVDS or LVCMOS outputs - its pinout and internal routing are optimized for high-speed, low-skew LVPECL distribution. Each output pair (e.g., CLKout0/CLKout0*) is independently programmable via dedicated divider blocks.

What reference input redundancy features does the LMK04111SQ/NOPB offer?

The LMK04111SQ/NOPB provides dual differential reference inputs (CLKin0/CLKin0* and CLKin1/CLKin1*) with hardware-supported automatic switchover and manual selection modes. Each input includes dedicated loss-of-signal (LOS) detection circuitry, with status reported on separate open-drain LVCMOS pins (CLKin0_LOS and CLKin1_LOS). The LMK04111SQ/NOPB maintains lock during seamless transitions and supports holdover operation using the internal VCO when both references are lost - critical for carrier-grade basestation uptime.

Is the LMK04111SQ/NOPB compatible with the MICROWIRE serial interface?

Yes, the LMK04111SQ/NOPB uses a 3-wire MICROWIRE-compatible interface (CLKuWire, DATAuWire, LEuWire) for register programming. It supports standard MICROWIRE timing with minimum setup/hold requirements (25 ns setup, 8 ns hold) and latch-enable synchronization. The interface allows full configuration of PLL dividers, output formats, and control registers without requiring JTAG or complex protocols. All register writes to the LMK04111SQ/NOPB are performed through this interface, and it remains functional during normal operation.