LMX2572 - 6.4GHz Low-Power Wideband RF Synthesizer

The LMX2572 is a low-power, high-performance wideband synthesizer that can generate anyfrequency from 12.5 MHz to 6.4 GHz without using an internal doubler. The PLL delivers excellentperformance while consuming just 75 mA from a single 3.3-V supply.

For applications like digital mobile radio (DMR) and wireless microphones, the LMX2572supports FSK modulation. Discrete level FSK and pulse-shaping FSK are supported. Direct digital FSKmodulation is achievable through programming or pins.

The LMX2572 allows users to synchronize the output of multiple devices and also enablesapplications that need deterministic delay between input and output. An option is provided toadjust the phase with fine granularity to account for delay mismatch on the board or withindevices. A frequency ramp generator can synthesize up to 2 segments of ramp in an automatic rampgeneration option or a manual option for maximum flexibility. The fast calibration algorithm allowschanging frequencies faster than 20 µs. The LMX2572 also supports generating or repeating SYSREF(compliant to JESD204B standard) making it an ideal low-power, low-noise clock source for clockinghigh-speed data converters. Fine delay adjustment is provided in this configuration to account fordelay differences of board traces.

The LMX2572 integrates LDOs from a single 3.3-V supply, thus eliminating the need foronboard low-noise LDOs.

• Output Frequency: 12.5 MHz to 6.4 GHz
• Low Power Consumption: 75 mA at 3.3-V Supply
• –106-dBc/Hz Phase Noise at 100-kHz Offset With 6.4-GHz Carrier
• PLL Figure of Merit: –232 dBc/Hz
• PLL Normalized 1/f Noise: –123.5 dBc/Hz
• 32-Bit Fractional-N Divider
• Remove Integer Boundary Spurs With Programmable Input Multiplier
• Synchronization of Output Phase Across Multiple Devices
• Support for JESD204B SYSREF With Programmable Delay
• Support for Ramp and Chirp Functions
• Support for FSK Direct Digital Modulation
• Two Programmable Output Power Level Differential Outputs
• Fast VCO Calibration Speed: < 20 µs
• Single 3-V to 3.5-V Power Supply

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