EuMW 2015: Jitter attenuator targets base stations

The JESD204B interface was specifically developed to address high-data rate system design needs, and the 3.2-GHz HMC7044 clock jitter attenuator contains functions that support and enhance the unique capabilities of that interface standard.

The HMC7044 delivers 50-fs jitter performance, which improves the signal-to-noise ratio and dynamic range of high-speed data converters, and the device provides 14 low-noise and configurable outputs that provide flexibility in interfacing with many different components. 

TheHMC7044 also offers a wide range of clock management and distribution features that make it possible for designers of base stations to build an entire clock design with a single device.

In base stations applications there are many serial JESD204B data converter channels that require their data frames to be aligned with an FPGA. This new clock jitter attenuator simplifies JESD204B system design by generating source-synchronous and adjustable sample and frame alignment (SYSREF) clocks in a data converter system.

The device features two phase-locked loops (PLLs) and overlapping, on-chip, voltage-controlled oscillators (VCOs). The first PLL locks a low-noise, local voltage-controlled clock oscillator (VCXO) to a relative noisy reference, while the second PLL multiplies the VCXO signal up to the VCO frequency with exceptionally little added noise.

For cellular infrastructure JESD204B clock generation, wireless infrastructure, data converter clocking, microwave baseband cards and other high-speed communications applications, the architecture of the HMC7044 offers excellent frequency generation performance with low phase noise and integrated jitter.

Key Features include ultra-low RMS jitter of 50 fs (12 KHz to 20 MHz, typical) and low phase noise of < -142 dBc/Hz at 800 kHz to 983.04 MHz output frequency’. There are up to 14 device differential device clocks from PLL2 and the external VCO input supports up to 5 GHz.