New Content (1)
Product Selection GuideRF, Microwave, and Millimeter Wave IC Selection Guide 2018
Features and Benefits
- LTC6955: 11 Output Buffer
- LTC6955-1: 10 Buffered Outputs and One ÷2 Output
- Additive Output Jitter ~45fs RMS (ADC SNR Method)
- Additive Output Jitter < 5fs RMS (Integration BW = 12kHz to 20MHz, f = 7.5GHz)
- Eleven Ultralow Noise CML Outputs
- Parallel Control for Multiple Output Configurations
- –40°C to 125°C Operating Junction Temperature Range
The LTC6955 is a high performance, ultralow jitter, fanout clock buffer with eleven outputs. Its 4-pin parallel control port allows for multiple output setups, enabling any number between three and eleven outputs, as well as a complete shutdown. The parallel port also provides the ability to invert the output polarity of alternating outputs, simplifying designs with top and bottom board routing.
Each of the CML outputs can run from DC to 7.5GHz. The LTC6955-1 replaces one output buffer with a divide-by-2 frequency divider, allowing it to drive Linear Technology’s LTC6952 or LTC6953 to generate JESD204B subclass 1 SYSREF signals. These SYSREFs can pair with ultralow jitter device clocks from the LTC6955-1, which can run at frequencies up to 7.5GHz.
- High Performance Data Converter Clocking
- SONET, Fibre Channel, GigE Clock Distribution
- Low Skew and Jitter Clock and Data Fanout
- Wireless and Wired Communications
- Single-Ended to Differential Conversion
Product Lifecycle Pre-Release
This product is new and engineering validation may still be underway. Quantities may be limited and design specifications may change while we ready the product for release to production.
Evaluation Kits (2)
Demonstration Circuit 2611A features the LTC6955/LTC6955-1, Ultralow Jitter 11 Output Fanout Buffers.
By default, the DC2611A is powered from a single 3.3V supply. An option is provided to power to the DC2611A from dual supplies, allowing for the LTC6955’s output supply pins to connect to an LTC Silent Switcher® and the LTC6955 input supply pin to connect to a low noise LDO.
The differential inputs and six of the differential outputs are populated with 0.5" spaced SMA connectors. These outputs are AC-coupled with 50Ω transmission lines making them suitable to drive 50Ω impedance instruments. All registered trademarks and trademarks are the property of their respective owners.
The remaining four differential outputs are terminated with 100Ω.
A calibration path is provided to aid in accurate LTC6955 propagation delay measurements. The calibration path can be also reconfigured as a DC path, which allows for a convenient method of locking the LTC6955 outputs to an external PLL/VCO.
Demonstration circuit 2664A is a VCO Rider Board with Loop Filter that supports the popular 0.5" × 0.5" VCO package footprint.
The DC2664A expedites evaluation of Phase-Locked Loop (PLL) devices requiring an external Voltage Controlled Oscillator (VCO). Without the DC2664A, each VCO and PLL combination requires a unique loop filter design, resulting in several PLL demo board modifications to evaluate each VCO. These board modifications are time consuming and often result in damage to either the PLL or the VCO.
The DC2664A integrates the VCO and loop filter allowing these unique designs to reside on multiple DC2664As. The DC2664A RFOUT and VTUNE SMA connections allow the user to quickly evaluate a PLL with multiple VCOs without risk of damage from multiple board modifications. VCOs are notoriously sensitive to power supply noise and spurs. The DC2664A resolves the concern of locating a low noise and low spurious lab supply by powering the VCO with an onboard ultralow noise and ultrahigh PSRR LDO, the LT3042. A second LT3042 LDO is available on the DC2664A to power an active loop filter. Both LDOs are powered from a single supply, simplifying the number of lab supplies required to evaluate a VCO and PLL combination.
The DC2664A was designed to mate directly with the LTC6955 (DC2611A) and LTC6952 (DC2609A) demo boards.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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.