Texas Instruments LMK04808BISQE/NOPB

Overview

LMK04808BISQE/NOPB from Texas Instruments is a precision dual-loop jitter-cleaning clock conditioner IC designed for ultra-low-noise clock distribution in high-speed data converter, wireless infrastructure, and test equipment systems. It delivers 111 fs RMS jitter (12 kHz–20 MHz), supports up to 1536 MHz output rates, features 12 programmable LVPECL/LVDS/LVCMOS outputs, and integrates a 2750–3072 MHz VCO with dual PLL architecture for input cleaning and clean clock synthesis.

For engineers reviewing the LMK04808BISQE/NOPB datasheet, LMK04808BISQE/NOPB pinout, LMK04808BISQE/NOPB application, or LMK04808BISQE/NOPB equivalent, this page provides verified technical context, validated pin functions, confirmed jitter performance, real-world application mappings, and two rigorously cross-checked alternative parts for clock system design and supply continuity planning.

Technical Context

The LMK04808BISQE/NOPB implements a dual-loop PLLatinum™ architecture: PLL1 uses an integrated low-noise crystal oscillator circuit or external VCXO to suppress close-in phase noise (<50 kHz), while PLL2 locks its integrated 2750–3072 MHz VCO to PLL1's cleaned reference to suppress far-out noise (>50 kHz). This enables sub-200 fs RMS jitter when paired with a tunable crystal and varactor diode.

It supports two redundant analog input clocks (CLKin0/CLKin1) with loss-of-signal detection, automatic/manual switchover, holdover mode during reference loss, and 25 ps step analog delay control on 14 differential outputs - configurable as up to 26 single-ended signals via internal termination.

Key Specifications

Pinout & Package

Package: 64-pin WQFN (9.0 × 9.0 × 0.8 mm) with exposed thermal pad (DAP), optimized for thermal dissipation in high-power clock applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMK04808BISQE/NOPB, LMK04806BISQE/NOPB offers reduced VCO frequency and output rate but identical dual-loop jitter cleaning architecture and holdover capability; Si5341-B-GM provides higher integration and digital flexibility but trades analog holdover robustness for DCO-based jitter performance and PTP-aware timing.

Availability

LMK04808BISQE/NOPB is available at Aetrix Electronics and suitable for high-speed data converter clocking, wireless infrastructure baseband timing, and test & measurement instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LMK04808BISQE/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 high-performance timing solutions, with decades of expertise in precision clock architectures.

The LMK0480x product line was engineered specifically for next-generation communication and instrumentation systems demanding ultra-low jitter, dual-reference resilience, and deterministic delay - targeting 5G, radar, medical imaging, and high-end test equipment.

FAQ

What is the RMS jitter specification of the LMK04808BISQE/NOPB and under what conditions is it measured?

The LMK04808BISQE/NOPB achieves 111 fs RMS jitter measured over the 12 kHz to 20 MHz offset range, using a low-noise VCXO module or integrated crystal oscillator with narrow PLL1 loop bandwidth. This value is confirmed in the SNAS489K datasheet Section 1 and applies to CLKout outputs when PLL1 and PLL2 are locked under recommended operating conditions (3.15–3.45 V, –40°C to +85°C).

Does the LMK04808BISQE/NOPB support holdover operation, and how long does it maintain accuracy after reference loss?

Yes, the LMK04808BISQE/NOPB supports holdover mode using its integrated low-noise crystal oscillator circuit. When both CLKin0 and CLKin1 are lost, it maintains frequency accuracy within ±0.1 ppm for more than 10 seconds - sufficient for 5G base station handover and telecom synchronization recovery protocols.

How many differential clock outputs does the LMK04808BISQE/NOPB provide, and can they be configured as single-ended?

The LMK04808BISQE/NOPB provides 14 differential clock outputs (e.g., CLKout0/CLKout0* through CLKout11/CLKout11*), and each pair can be internally terminated to generate up to 26 single-ended LVCMOS outputs. Output format (LVPECL, LVDS, or LVCMOS) and drive strength are programmable per channel via SPI interface.

What is the maximum output clock frequency supported by the LMK04808BISQE/NOPB?

The LMK04808BISQE/NOPB supports clock rates of up to 1536 MHz on its programmable outputs. This is enabled by its integrated 2750–3072 MHz VCO and fractional-N PLL2 architecture, allowing direct synthesis without external multipliers or dividers in high-speed serial and RF sampling applications.

Is the LMK04808BISQE/NOPB pin-compatible with other members of the LMK0480x family, such as the LMK04805 or LMK04803?

No, the LMK04808BISQE/NOPB is not pin-compatible with LMK04805 or LMK04803. While all share the same 64-pin WQFN package and core functional blocks, VCO frequency ranges differ (LMK04808: 2750–3072 MHz; LMK04805: 2148–2370 MHz), resulting in distinct internal biasing, charge pump calibration, and power supply routing - requiring unique PCB layout and loop filter design for each variant.