LMX2542 Datasheet | National Semiconductor

Description LMX2542 is a highly integrated, high performance, low power frequency synthesizer system optimized for Cellular CDMA 1x RTT and IS-95 mobile handsets and data systems with GPS capabilities. Using a proprietary digital phase locked loop technique, LMX2542 provides very stable, low noise local oscillator (LO) signals for up and down conversion in wireless munications devices. LMX2542 includes a Voltage Controlled Oscillator (VCO) for both the Cellular-CDMA and GPS frequency bands, a loop filter, and a Fractional-N RF PLL based on a Delta Sigma (∆Σ) modulator. In concert, these blocks form a closed loop RF synthesizer system. The RF synthesizer system operates from 2087.73 MHz to 2155.14 MHz. LMX2542 includes an Integer-N IF PLL also. For more flexible loop filter designs, the IF PLL includes a 4-level programmable charge pump. Together with an external VCO and loop filter, LMX2542 makes a plete closed loop IF synthesizer system. The default IF frequency is 367.20 MHz. Serial data is transferred to the device via a three-wire MICROWIRETM interface (DATA, LE, CLK). Operating supply voltage ranges from 2.7V to 3.3V. LMX2542 features low current consumption: 22 m A at 2.8V. LMX2542 is available in a 28-Pin Leadless Leadframe Package (LLP). Features n Small Size 5.0 mm x 5.0 mm x 0.75 mm 28-Pin LLP n RF Synthesizer System Integrated RF VCO Integrated Loop Filter Low Spurious, Low Phase Noise Fractional-N RF PLL Based on 11-Bit ∆Σ modulator 5 k Hz Frequency Resolution Cellular-CDMA LO: 2105.28 MHz to 2155.14 MHz (Requires an External LO /2 Circuit) GPS LO: 2087.73 MHz (Requires an External LO /1.5 Circuit) n IF Synthesizer System Integer-N IF PLL Programmable Charge Pump Current Levels IF LO: 367.20 MHz n Supports Various Reference Oscillator Frequencies: 19.20 MHz/ 19.68 MHz n Low Current Consumption: 22 m A typical at 2.8V n 2.7V to 3.3V Operation n RF Digital Filtered Lock Detect Output n Hardware and Software Powerdown Control Applications n Cellular-CDMA 1x...