250 MHz to 12.4 GHz fractional/integer-N PLL

January 13, 2014 // By Graham Prophet
MAX2880 is a high-performance phase-locked loop (PLL) capable of operating in both integer-N and fractional-N modes. Combined with an external reference oscillator, loop filter, and VCO, the device forms an ultra-low noise and low-spur frequency synthesiser capable of accepting RF input frequencies of up to 12.4 GHz.

It comprises a high-frequency and low-noise-phase frequency detector (PFD), precision charge pump, 10-bit programmable reference counter, 16-bit integer N counter, and 12-bit variable modulus fractional modulator. The device is controlled by a 3-wire serial interface and is compatible with 1.8 V control logic. It comes in a 4 x 4 mm, 20-pin TQFN package, and operates over an extended -40 to +85C temperature range.

It is suitable for use in microwave point-to-point systems. wireless infrastructure, satellite communications, test and measurement, and in RF DAC and ADC clocks. Features include integer and fractional-N modes, 250 MHz to 12.4 GHz broadband RF input, reference frequency up to 205 MHz, cycle slip reduction and fast lock, software and hardware shutdown, software lock detect, and phase adjustment.

Normalized in-band noise floor is -229 dBc/Hz in integer mode and -227 dBc/Hz in fractional mode. Input sensitivity ranges from -10 dBm to +5 dBm.

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