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ADCLK944:  2.5 V/3.3 V, Four LVPECL Outputs, SiGe Clock Fanout Buffer

Product Details

Product Status:Recommended for New Designs

The ADCLK944 is an ultrafast clock fanout buffer fabricated on the Analog Devices, Inc., proprietary XFCB3 silicon germanium (SiGe) bipolar process. This device is designed for high speed applications requiring low jitter.

The device has a differential input equipped with center-tapped, differential, 100 Ω on-chip termination resistors. The input can accept dc-coupled LVPECL, CML, 3.3 V CMOS (single-ended), and ac-coupled 1.8 V CMOS, LVDS, and LVPECL inputs. A VREF pin is available for biasing ac-coupled inputs.

The ADCLK944 features four full-swing emitter-coupled logic (ECL) output drivers. For LVPECL (positive ECL) operation, bias VCC to the positive supply and VEE to ground. For ECL operation, bias VCC to ground and VEE to the negative supply.

The ECL output stages are designed to directly drive 800 mV each side into 50 Ω terminated to VCC − 2 V for a total differential output swing of 1.6 V.

The ADCLK944 is available in a 16-lead LFCSP and is specified for operation over the standard industrial temperature range of −40°C to +85°C. Applications

  • Low jitter clock distribution
  • Clock and data signal restoration
  • Level translation
  • Wireless communications
  • Wired communications
  • Medical and industrial imaging
  • ATE and high performance instrumentation


  • Operating frequency: 7.0 GHz
  • Broadband random jitter: 50 fs rms
  • On-chip input terminations
  • Power supply (VCC − VEE): 2.5 V to 3.3 V

Functional Block Diagram for ADCLK944


Title Content Type File Type
ADCLK944: 2.5 V/3.3 V, Four LVPECL Outputs,SiGe Clock Fanout Buffer (Rev 0, 03/2010) (pdf, 220 kB) Data Sheets PDF
MT-008: Converting Oscillator Phase Noise to Time Jitter  (pdf, 123 kB) Tutorials PDF
UG-125: Setting Up the Evaluation Board for the ADCLK944  (pdf, 171 kB) User Guides PDF
Speedy A/Ds Demand Stable Clocks
by Jeff Keip, Analog Devices, Inc. (EE Times, 3/18/04)
Technical Articles HTML
Design A Clock-Distribution Strategy With Confidence
by Demetrios Efstathiou (Electronic Design, April 27, 2006)
Technical Articles HTML
Understand the Effects of Clock Jitter and Phase Noise on Sampled Systems
... Much of your system's performance depends on jitter specifications, so careful assessment is critical.
by Brad Brannon, Analog Devices (EDN, 12/7/2004)
Technical Articles HTML
Clock Requirements For Data Converters
(Electronic Design, 2/2005)
Technical Articles HTML
Termination of High-Speed Converter Clock Distribution Devices
(The Back Burner, January 2010)
Analog Dialogue HTML
Analog-to-Digital Converter Clock Optimization: A Test Engineering Perspective
(Analog Dialogue, Vol. 42, February 2008)
Analog Dialogue HTML
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
ADIsimCLK Design and Evaluation Software
ADIsimCLK is the design tool developed specifically for Analog Devices' range of ultra-low jitter clock distribution and clock generation products. Whether your application is in wireless infrastructure, instrumentation, networking, broadband, ATE or other areas demanding predictable clock performance, ADIsimCLK will enable you to rapidly develop, evaluate and optimize your design.
ADIsim Design/Simulation Tools HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

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Price, packaging, availability

ADCLK944 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
ADCLK944BCPZ-R2 Status: Production 16 ld LFCSP (3x3mm, 1.5mm exposed pad) 16 Ind Reel, 250 $3.76 $3.76 Y  Material Info PCN Purchase
ADCLK944BCPZ-R7 Status: Production 16 ld LFCSP (3x3mm, 1.5mm exposed pad) 16 Ind Reel, 1500 $3.76 $3.20 Y  Material Info PCN Purchase
ADCLK944BCPZ-WP Status: Production 16 ld LFCSP (3x3mm, 1.5mm exposed pad) 16 Ind Tray, 50 $3.76 $3.20 Y  Material Info Notify Me Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

ADCLK944 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
ADCLK944/PCBZ Status: Production Evaluation Board $190.00 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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