1.58 GHz PLL frequency synthesizer for RF local-oscillator chains
The Texas Instruments LMX2531LQ1515E/NOPB is a high-performance PLL-based frequency synthesizer designed for RF applications. It accepts a clock input and delivers a CMOS output up to 1.58 GHz, making it a fit for local-oscillator generation in wireless infrastructure, test equipment, and satellite downconverters. The part integrates the PLL function (Yes) in a single 1-circuit device with a 2:2 input-to-output ratio, and operates from a 2.8V to 3.2V supply rail over the industrial temperature range of -40°C to 85°C.
Supply and temperature — what the ratings mean for the BOM
The 2.8V to 3.2V supply window is tighter than a typical 3.3V ±10% rail. If your board runs a 3.3V bus, you need a local LDO or a low-dropout regulator set to 3.0V to stay inside the operating range. The -40°C to 85°C rating covers outdoor telecom cabinets, base-station shelters, and automotive cabin environments — but not under-hood or engine-bay applications, which would require a 125°C-rated part.
Package and footprint — 36-WQFN with exposed pad
Housed in a 36-WFQFN Exposed Pad package (6x6 mm body per the supplier device package designation), this is a surface-mount part that requires a thermal pad on the PCB for heat sinking. The exposed pad must be soldered to a ground plane with adequate via stitching to carry dissipation.
Lifecycle and sourcing
The LMX2531LQ1515E/NOPB carries an Active product status per the manufacturer.