LMX2354TMX/NOPB

Clock Generators, PLLs, Frequency Synthesizers Overview

The LMX2354TMX/NOPB is a dual low-power PLLatinum FractionalN/IntegerN frequency synthesizer designed for local oscillator subsystems. It operates with supply voltages from 2.7V to 5.5V and supports RF frequencies between 0.5 GHz and 2.5 GHz, and IF frequencies between 10 MHz and 550 MHz. The device features programmable charge pump currents ranging from 100 µA to 1.6 mA in 100 µA steps for the RF loop, and selectable levels of 100 µA or 800 µA for the IF loop. Typical current consumption is 7 mA at 3V in dual-PLL mode, reducing to 5 µA in power-down mode. It utilizes a Microwire serial interface for configuration.

Clock Generators, PLLs, Frequency Synthesizers Feature Summary

• Dual independent phase-locked loops supporting fractional N and integer N synthesis modes
• Enhanced low noise fractional engine with modulo 15 or 16 compensation circuitry
• Programmable charge pump output currents with configurable polarity and voltage doubler support
• Digital filtered lock detect function with multiplexed output capability

Clock Generators, PLLs, Frequency Synthesizers Applications

• Portable wireless communications systems including PCS and PCN
• Dual mode cellular telephone systems
• Zero blind slot TDMA systems
• Spread spectrum communication systems such as CDMA
• Cable TV tuners (CATV)

Clock Generators, PLLs, Frequency Synthesizers Procurement Notes

Verify component authenticity through authorized Texas Instruments channels or certified distributors. Confirm the presence of the NOPB suffix indicating lead-free compliance and RoHS adherence. Inspect the TSSOP-24 package integrity upon receipt. Ensure handling procedures account for ESD sensitivity ratings below 2kV during storage and assembly operations.

Clock Generators, PLLs, Frequency Synthesizers Selection Notes

Evaluate the required operating frequency range to determine if the 2.5 GHz RF limit meets system specifications. Assess power budget requirements against the typical 7 mA consumption profile. Verify compatibility with the Microwire serial interface protocol for control logic integration. Consider the availability of external VCOs compatible with the programmable charge pump drive capabilities.

Clock Generators, PLLs, Frequency Synthesizers Part Context

This component belongs to the Texas Instruments LMX235x family of PLLatinum synthesizers. It serves as a functional equivalent to the LMX2350 but includes specific architectural modifications such as different prescaler configurations and enhanced fractional compensation features. The device represents an evolution in low-power RF frequency synthesis technology for mobile applications.

Clock Generators, PLLs, Frequency Synthesizers Replacement Considerations

The LMX2354 is pin-compatible with the LMX2350. When substituting, ensure that register bit assignments for the A counter are adjusted due to differences in modulus prescaler selection between the two devices.