Clock Distributor

Clock Distributor: Effectively Synchronize Your System with a Clock Distributor

To ensure the different electronic sections of one’s system are synchronized correctly one must employ an effective clocking strategy. This is especially true when building test and measurement equipment like a multichannel high data rate PRBS / pattern generator. Not only do parts in series in each channel need to communication correctly to avoid errors, but each channel in most cases need to be phased matched to each other.

Only a high performance clock distributor with very precise phase matched operation can perform the important task of successfully synchronizing a system’s components together. While several passive solutions exist on the market today that can accomplish this job, they tend to be bulky and always introduce some level of unwanted signal loss. When operating at GHz speeds, any loss is not desired since plenty occurs due to other ever present loss contributors like PCB, connectors, IC packaging, etc. An active approach is beneficial since they consume less space and provide much needed signal amplification / restoration.

The ASNT5023-KMM from ADSANTEC Inc. is an 1 channel to 4 channel active clock distributor that functions with input clock frequencies up to 17GHz. The device takes the input clock signal and actively creates 4 replicas of it and sends them to its four in parallel outputs. Since the four output channels are designed to match each other, the resulting four output signals are fully phase matched.

All I/Os are CML with each single port featuring internal 50ohm termination to the power supply. The differential I/Os can be used both single-ended or differentially using DC blocks when appropriate (see the part’s datasheet for more information). The clock distributor can process input signals with amplitudes as low as 50mVpk-pk (differential or single-ended) and still produce maximum output signal amplitudes of 600mVpk-pk single-ended (1.2Vpk-pk differential). Rise/fall times of the outputs are in the 15ps range.

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