LMKDB1104Z85REXT

Overview

The LMKDB1104Z85REXT is a low-power LP-HCSL clock buffer from Texas Instruments, designed for PCIe Gen 1 to Gen 7 architectures. It features one differential input and four differential outputs with a fixed 85Ω output impedance. The device supports flexible power-up sequences, individual output enables, and automatic output disable upon loss of signal (LOS). It operates on a single 1.8V or 3.3V supply within an ambient temperature range of -40°C to 105°C.

Feature Summary

• LP-HCSL clock buffer supporting PCIe Gen 1 through Gen 7 standards
• Fixed 85Ω differential output impedance compliant with DB2000QL specifications
• Fail-safe inputs ensuring safe states during invalid input conditions
• Individual active-low output enable pins (^OE0# to ^OE3#) with internal pullups

Applications

• High Performance Computing systems
• Server Motherboard clock distribution
• NIC and SmartNIC designs
• Hardware Accelerator clocking

Procurement Notes

Verify the REXT suffix indicates the specific reel packaging configuration required for surface-mount assembly. Confirm that the Z85 designation corresponds to the 85Ω impedance variant, as other impedance options exist within the family. Ensure compatibility with the target PCB layout guidelines provided in the datasheet for optimal signal integrity.

Selection Notes

Select this component when a 1-to-4 fan-out is required with fixed 85Ω termination. Unlike the MUX variants in the LMKDB12xx series, this device lacks dual-input switching capabilities. It is suitable for applications requiring independent control of each output channel via dedicated hardware pins rather than SMBus/SBI interfaces.

Part Context

This part belongs to the LMKDB family of ultra-low jitter clock buffers and muxes. While the LMKDB12xx series provides multiplexing functionality with selectable impedance, the LMKDB11xx series focuses on buffering with fixed impedances. The LMKDB1104 specifically offers four outputs, whereas the LMKDB1108 provides eight.

Replacement Considerations

LMKDB1104Z100: Provides identical functionality but with a selectable 100Ω output impedance instead of 85Ω.