LTC6955

Demonstration Circuit 2611A features the LTC6955, 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.

Demonstration Circuit 2611A features the 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 LTC6955-1’s output supply pins to connect to an LTC Silent Switcher® and the LTC6955-1 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 LTC6955-1 propagation delay measurements. The calibration path can be also reconfigured as a DC path, which allows for a convenient method of locking the LTC6955-1 outputs to an external PLL/VCO.