LMX2571NJKT

The LMX2571 is a low-power, high-performance, wideband PLLatinum™ radio frequency (RF) synthesizer that integrates a Δ-Σ fractional-N PLL, a multi-core voltage-controlled oscillator (VCO), a programmable output divider, and two output buffers. The VCO core operates at frequencies up to 5.376 GHz, with a continuous output frequency range from 10 MHz to 1344 MHz. The synthesizer can also be used with an external VCO. In this configuration, a dedicated 5V charge pump and output divider are required. The synthesizer also includes a unique programmable multiplier that helps eliminate glitches, allowing the system to use either channel even if the glitches fall on integer boundaries. Its output features an SPDT switch that can be used as a transmit/receive switch in FDD radio applications. Two switches can be turned on simultaneously to provide dual outputs. The LMX2571 supports direct digital FSK modulation through programming or corresponding pins. The device supports discrete-level FSK, pulse-shaped FSK, and analog FM modulation. The device uses a new FastLock technology that enables users to switch from one frequency to another in less than 1.5 ms, even when an external VCO is used with a narrowband loop filter.

Applications

• Duplex-mode digital professional two-way radio – dPMR, DMR, PDT, P25 Phase I
• Low-power radio communication systems
• Satellite communication modems
• Wireless microphones
• Proprietary wireless connectivity
• Handheld test and measurement equipment

Key features

• Output frequency range: 10MHz to 1344MHz
• Low phase noise and spurs
• –123dBc/Hz at 12.5kHz offset @480MHz, –145dBc/Hz at 1MHz offset @480MHz, normalized PLL noise floor of –231dBc/Hz, spurious better than –75dBc/Hz
• New FastLock technology for reduced lock time
• New integer boundary spur suppression technology
• Integrated 5V charge pump and output driver for external VCO operation
• 2-, 4-, and 8-level or arbitrary level direct digital FSK modulation
• One TX/RX output or two fanout outputs
• 39mA typical synthesizer mode (internal VCO)
• 9mA typical PLL mode (external VCO)
• Crystal, XO, or differential reference clock input
• Low current consumption
• 24-bit fractional-N Δ-Σ modulator