LMKDB1204REXT

Overview

The LMKDB1204REXT is a PCIe clock buffer and multiplexer from Texas Instruments, designed for Gen 1 through Gen 7 architectures. It features two differential clock inputs and four LP-HCSL outputs with selectable 85Ω or 100Ω impedance. The device supports Common Clock (CC) and Independent Reference (IR) topologies, including input clocks with Spread Spectrum Clocking (SSC). Key electrical characteristics include extremely low additive jitter, reaching 2.1fs maximum for PCIe Gen 7 applications. It operates on a single 1.8V or 3.3V ±10% supply within an ambient temperature range of –40°C to 105°C.

Feature Summary

• Supports PCIe Gen 1 to Gen 7 with CC and IR architectures
• Extremely low additive jitter: 2.1fs max for PCIe Gen 7
• Dual differential inputs with four LP-HCSL outputs
• Selectable output impedance (85Ω or 100Ω)
• Fail-safe inputs and flexible power-up sequence

Applications

• High Performance Computing
• Server Motherboard
• NIC/SmartNIC
• Hardware Accelerator

Part Context

The LMKDB1204REXT belongs to the LMKDB11xx family of ultra-low jitter LP-HCSL clock buffers and muxes. This family is compliant with Intel DB2000QL specifications. While other variants in the series are pin-compatible with legacy devices like the DB2000QL or DB1206, the LMKDB1204 specifically functions as a 2-to-4 multiplexer rather than a simple fan-out buffer.

Replacement Considerations

The LMKDB1204 is part of the LMKDB11xx family which maintains backward compatibility with CDCLVC110x series devices. For direct replacements, verify if the application requires a buffer or a multiplexer function, as the LMKDB1204 provides 2-input selection capabilities unlike standard buffers.