Multiple-Output Clock Generator with Spread Spectrum

Active: In Production.

The MAX9492 frequency synthesizer is designed to generate multiple clocks for clock distribution in network routers or switches. The device provides a total of six buffered clock outputs (CLK1 to CLK6). CLK1 is the buffered output of the reference clock. CLK2 through CLK6 are independently programmable to generate eight different frequencies based on a 25MHz input crystal: 133, 125, 83, 66, 62.5, 50, 33, and 25MHz. All the outputs are LVCMOS single-ended signals. Either a 25MHz crystal or an external clock can serve as the input reference clock. The MAX9492 incorporates two phase-locked loops (PLLs) with two internal loop filters.

Select the MAX9492's output clock frequency by programming on-chip registers through the MAX9492's I²C interface. The device also features spread-spectrum capability to reduce electromagnetic interference (EMI). This technique allows spreading the fundamental energy over a wider frequency range, hence reducing the respective energy amplitude. The output frequency spectrum is downspread by -1.25% or -2.5%.

The MAX9492 operates from a 3.3V supply and is guaranteed over the extended temperature range (-40°C to +85°C). The device is available in a space-saving, 20-pin, TQFN, 5mm x 5mm package.

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