Provides additive jitter of less than 20fs _RMS in the 12kHz ~ 20MHz bandwidth

Linear announced the release of a family of very low-jitter 1.8GHz clock splitter chips with three independent outputs (product name: LTC6954 ). Providing additive jitter of less than 20fs _RMS across a bandwidth of 12kHz to 20MHz, the LTC6954 splits and distributes the input clock while minimizing the amount of introduced noise.

Through this feature, the LTC6954 can provide a low-jitter clock essential for achieving optimal signal-to-noise ratios (SNR) when driving high-resolution data converters. For example, low-jitter ADC clocking is critical when digitizing analog high frequencies, such as RF or high IF signals, and the LTC6954 provides an ideal clocking solution for such systems.

The LTC6954 family includes four versions and offers various combinations of LVPECL and LVDS/CMOS output logic drives. These features provide the flexibility to optimally connect numerous devices that accommodate different logic signals. Powered by a single 3.3V supply and programmed via SPI, the LTC6954 independently divides the input clock into integers between 1 and 63 and also provides the capability to independently delay each output for input clock cycles from 0 to 63. This characteristic is used to generate the phase-shift clock essential for driving the I and Q channel analog-to-digital converters (ADCs) in communication systems.


▶ Clock divider with additive jitter of less than 20fs _RMS (Source: Linear)

In addition to its performance as an independent clock divider, the LTC6954 provides Linear Technology’s proprietary EZSync ^™ synchronization technique. EZSync synchronization, triggered by a simple pulse, adjusts the rising edges of multiple outputs on a single or multiple chips to create a repetitive and deterministic phase relationship between all clock divider outputs. The LTC6954 can be paired with the LTC6950 as a successor that extends the number of clock outputs adjusted to the low jitter edges generated by the LTC6950.

The LTC6954 is specialized for a full operating junction temperature range of –40°C to 105°C and is available in a 4mm × 7mm, 36-pin plastic QFN package. It is currently in mass production and is priced at $7.50 per unit in 1,000-unit quantities. Samples and demo boards can be requested by visiting www.linear.com/product/LTC6954 or by contacting your local Linear Technology office.