LMK1D1204PRHDT

Clock Buffers, Drivers Overview

The LMK1D1204PRHDT is a low additive jitter LVDS clock buffer manufactured by Texas Instruments. It features a 2:4 architecture, distributing one of two selectable inputs (IN0 or IN1) to four differential LVDS outputs. The device supports input frequencies up to 2 GHz and operates with supply voltages of 1.8 V, 2.5 V, or 3.3 V ± 5%. Key electrical specifications include a maximum propagation delay of 575 ps, output skew of 20 ps, and additive jitter less than 60 fs RMS at 156.25 MHz. It is housed in a 28-pin VQFN package.

Clock Buffers, Drivers Feature Summary

• 2:4 Architecture: Distributes one of two selectable clock inputs to four differential LVDS outputs.
• Low Additive Jitter: Maximum < 60 fs RMS in the 12 kHz to 20 MHz range at 156.25 MHz.
• Universal Inputs: Accepts LVDS, LVPECL, LVCMOS, HCSL, and CML signal types.
• Individual Output Control: Hardware pins allow independent enable/disable of each output for power reduction.

Clock Buffers, Drivers Applications

• Telecommunications and networking
• Medical imaging
• Test and measurement
• Wireless infrastructure
• Pro audio, video and signage

Clock Buffers, Drivers Procurement Notes

Verify the ordering suffix 'RHDT' corresponds to the specific tape-and-reel packaging configuration required for the assembly process. Confirm that the component meets RoHS compliance standards as specified in the manufacturer's documentation. Ensure the procurement source provides valid traceability for the production lot.

Clock Buffers, Drivers Selection Notes

Select this component when individual output control is required, distinguishing it from the global-enable LMK1D1204 variant. Ensure the design accommodates the 28-pin VQFN package dimensions. Verify that the input signal levels match the supported universal input types and that the load impedance aligns with the 50-Ω transmission line design intent.

Clock Buffers, Drivers Part Context

The LMK1D1204P belongs to the LMK1D120x family of low additive jitter LVDS buffers. The 'P' suffix indicates pin-controlled output enables, whereas the standard LMK1D1204 uses global output enable. This family is designed for high-performance clock distribution with minimal skew and phase noise floor characteristics typical of -164 dBc/Hz.

Clock Buffers, Drivers Replacement Considerations

LMK1D1204RGTR: Offers similar buffering but utilizes a 16-pin VQFN package and global output enable control rather than individual pin control.

Clock Buffers, Drivers FAQ

How are unused outputs handled on the LMK1D1204P?

Unused outputs can be disabled via their corresponding OEx hardware pins, placing them in a high-Z state to reduce power consumption. If left enabled, TI recommends terminating them differentially with a 100-Ω resistor.

What is the function of the VAC_REF pins?

The VAC_REF pins provide a bias voltage output specifically for capacitive-coupled inputs. When used, a 0.1-µF capacitor to ground is recommended on these pins.

Can the LMK1D1204P accept single-ended inputs?

Yes, the device accepts LVCMOS, HCSL, and CML signals which may be single-ended. When driving inputs in single-ended mode, an appropriate bias voltage must be applied to the unused negative input pin.