Overview: SCL SDA
A0 FBCLK
A1 VDDD2 ADVANCED COMMUNICATIONS PRODUCT GROUP
Introduction
The ACS1790T is a high-performance, low phase noise, programmable frequency synthesizer with ultra-fine dynamic output frequency control. It can be used as a companion to a compatible ToPSync™ device to generate outputs locked to an external reference source or standalone for standard frequency generation for common applications. The circuit includes an integrated VCO, loop filter, phase-and-frequency detector and output dividers. The default power-up mode is definable by pin settings and once operational the ACS1790T is fully-programmable via an I2C interface. The ACS1790T requires only a low-speed external clock input for operation.
When used in conjunction with a compatible ToPSync® device in a Synchronous Ethernet system the ACS1790T allows the Ethernet transmit clocks to be derived initially from the local reference oscillator and subsequently frequency-locked to an external reference source once the system is fully configured, simplifying system design and reducing component count and BOM cost.
