LMX2502LQX1635

Overview

The LMX2502LQX1635 is a PLLatinum frequency synthesizer system with an integrated VCO, designed for PCS and Cellular CDMA applications. It operates within an output frequency range of 1.61962 GHz to 1.64962 GHz. The device supports a supply voltage between 2.7 V and 3.3 V, consuming approximately 17 mA of operating current. It is housed in a 28-pin WQFN package (5 mm x 5 mm) and is qualified under AEC-Q100 standards. The operational temperature range extends from -30°C to +85°C.

Feature Summary

• Integrates a phase-locked loop (PLL) and voltage-controlled oscillator (VCO) into a single highly compact system.
• Optimized specifically for generating local oscillator signals in Korean PCS and Cellular CDMA wireless applications.
• Features a small 5.0 mm x 5.0 mm x 0.75 mm 28-pin WQFN package for space-constrained designs.

Applications

• Korean PCS cellular phone systems
• Cellular CDMA base station and mobile unit local oscillators
• RF front-end modules requiring low-power frequency synthesis

Procurement Notes

Verify the specific suffix 'LQX' against the manufacturer's official ordering guide, as it denotes a fixed-frequency variant distinct from the standard LMX2502. Confirm that the component meets AEC-Q100 automotive qualification requirements if intended for vehicle electronics. Ensure the 28-WQFN footprint matches the PCB layout specifications precisely. Check for RoHS compliance status relative to the manufacturing date code. Validate that the fixed 1635 MHz center frequency aligns with the target network band requirements.

Selection Notes

Select this component when a fixed-frequency synthesizer is required for Korean PCS or CDMA bands, eliminating the need for external programmable logic. Consider the integrated VCO architecture for reduced bill-of-materials complexity compared to discrete solutions. Evaluate the 17 mA current consumption against battery life constraints in portable devices. Ensure the design can accommodate the thermal characteristics of the exposed pad WQFN package. Compare performance metrics such as phase noise against other members of the PLLatinum family if variable frequency operation is needed.

Part Context

The LMX2502 belongs to Texas Instruments' PLLatinum family of frequency synthesizers, which are known for high integration and low power consumption. This specific part number represents a fixed-frequency version optimized for the 1635 MHz band, differing from programmable variants like the LMX2502EVM. It shares architectural similarities with the LMX2512 but is tailored for specific regional communication standards. The device replaces older National Semiconductor RF ICs in modern cellular infrastructure and handsets.

Replacement Considerations

The LMX2502LQX1635/NOPB serves as a direct replacement for earlier versions of this fixed-frequency synthesizer. Verify pin-to-pin compatibility and electrical parameter equivalence before substitution. Ensure the replacement part maintains the same AEC-Q100 qualification level if used in automotive applications.