LMX2581 Wideband Frequency Synthesizer with Integrated VCO

LMX2581 Wideband Frequency Synthesizer with Integrated VCO
Industry’s Lowest Phase Noise Frequency Synthesizer

TI’s new LMX2581 wideband frequency synthesizer with integrated VCO outputs delivers the industry’s best phase noise performance. The LMX2581’s low noise PLL and industry’s highest phase detector frequency outperforms the competition to achieve the flexibility of a wideband frequency synthesizer without compromising system performance.

The highly-integrated LMX2581 combines a ?? fractional-N PLL, a multi-core VCO with tank circuit, optional frequency divider, two differential RF output buffers that can deliver +10 dBm single-ended on each side, and several low-noise, high-precision LDOs to enable lower cost systems in a number of applications, including wireless infrastructure, defense and aerospace, radar, test and measurement, and medical imaging.


The LMX2581 is a low noise wideband frequency synthesizer that integrates a delta-sigma fractional N PLL, multiple core VCO, programmable output divider, and two differential output buffers. The VCO frequency range is from 1880 to 3760 MHz and can be sent directly to the output buffers or divided down by even values from 2 to 38. Each buffer is capable of output power from –3 to +12 dBm at 2700 MHz. Integrated low noise LDOs are used for superior noise immunity and consistent performance.

This synthesizer is a highly programmable device and it enables the user to optimize its performance. In fractional mode, the denominator and the modulator order are programmable and can be configured with dithering as well. The user also has the ability to directly specify a VCO core or entirely bypass the internal VCO. Finally, many convenient features are included such as power down, Fastlock, auto mute, and lock detection. All registers can be programmed through a simple 3 wire interface and a read back feature is also available.

The LMX2581 operates on a single 3.3 V supply and comes in a 32 pin 5.0 mm x 5.0 mm WQFN package.

Part Numbers

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Source Texas Instruments

LMX2581 Wideband Frequency Synthesizer with Integrated VCO Datasheet and ordering information