LMK04800 Clock Conditioners



National Semiconductor's clock conditioners with superior clock jitter cleaning, generation, and distribution with advanced features to meet next generation system requirements

National Semiconductor LMK04800 Clock Conditioners National Semiconductor's LMK04800 family is the industry's highest performance clock conditioner with superior clock jitter cleaning, generation, and distribution with advanced features to meet next generation system requirements. The dual loop PLLatinum™ architecture enables 111 fs rms jitter (12 kHz to 20 MHz) using a low noise VCXO module or sub-200 fs rms jitter (12 kHz to 20 MHz) using a low cost external crystal and varactor diode. The dual loop architecture consists of two high-performance phase-locked loops (PLL), a low-noise crystal oscillator circuit, and a high-performance voltage controlled oscillator (VCO). The first PLL (PLL1) provides a low-noise jitter cleaner function while the second PLL (PLL2) performs the clock generation. PLL1 can be configured to either work with an external VCXO module or the integrated crystal oscillator with an external tunable crystal and varactor diode. When used with a very narrow loop bandwidth, PLL1 uses the superior close-in phase noise (offsets below 50 kHz) of the VCXO module or the tunable crystal to clean the input clock. The output of PLL1 is used as the clean input reference to PLL2 where it locks the integrated VCO. The loop bandwidth of PLL2 can be optimized to clean the far-out phase noise (offsets above 50 kHz) where the integrated VCO outperforms the VCXO module or tunable crystal used in PLL1.   LMK04800 Datasheet

  Features   Applications
  • Ultra-low RMS jitter performance
  • Dual loop PLLatinum PLL architecture
  • Two redundant input clocks with LOS
  • 50% duty cycle output divides, 1 to 1045 (even and odd)
  • LVPECL, LVDS, or LVCMOS programmable outputs
  • Precision digital delay, fixed or dynamically adjustable
  • Data converter clocking
  • Wireless infrastructure
  • Networking, SONET/SDH, DSLAM
  • Medical / video / military / aerospace
  • Test and measurement

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National Semiconductor
Part Number
Digi-Key
Part Number
Packaging VCO Frequency Package  
LMK04803BISQE/NOPB LMK04803BISQE/NOPBTR-ND Tape & Reel 1840 to 2030 MHz 64-WFQFN,
Exposed Pad
LMK04800 Datasheet
LMK04803BISQE/NOPBCT-ND Cut Tape
LMK04803BISQE/NOPBDKR-ND Digi-Reel
LMK04805BISQE/NOPB LMK04805BISQE/NOPBTR-ND Tape & Reel 2148 to 2370 MHz
LMK04805BISQE/NOPBCT-ND Cut Tape
LMK04805BISQE/NOPBDKR-ND Digi-Reel
LMK04806BISQE/NOPB LMK04806BISQE/NOPBTR-ND Tape & Reel 2370 to 2600 MHz
LMK04806BISQE/NOPBCT-ND Cut Tape
LMK04806BISQE/NOPBDKR-ND Digi-Reel
LMK04808BISQE/NOPB LMK04808BISQE/NOPBTR-ND Tape & Reel 2750 to 3072 MHz
LMK04808BISQE/NOPBCT-ND Cut Tape
LMK04808BISQE/NOPBDKR-ND Digi-Reel