Overview
The LMX2485ESQX/NOPB, produced by Texas Instruments, is a low-power, high-performance delta-sigma fractional-N PLL (Phase-Locked Loop) with an auxiliary integer-N PLL. This device is part of the PLLatinum™ family and is designed for applications requiring fine frequency resolution, low spurs, and fast programming speed. It is fabricated using Texas Instruments' advanced process technology, ensuring high resistance to temperature and process variations.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| RF PLL Frequency Range | 50 MHz to 3.0 GHz (LMX2485E) | |
| IF PLL Frequency Range | 75 MHz to 800 MHz | |
| Power Supply Voltage | 2.5 to 3.6 V | V |
| Operating Temperature | -40°C to 85°C | °C |
| Package Type | 24-lead 4.0 × 4.0 × 0.8 mm WQFN | |
| Current Consumption (ICC) | 5.0 mA (typical) | mA |
| Phase Detector Frequency | Up to 50 MHz | MHz |
| Fractional Modulus | 12-bit or 22-bit selectable | |
| Delta-Sigma Modulator Order | Up to 4th order programmable |
Key Features
- Advanced delta-sigma fractional compensation to push fractional spurs to higher frequencies outside the loop bandwidth.
- Quadruple modulus prescaler for lower divides: RF PLL (8/9/12/13 or 16/17/20/21) and IF PLL (8/9 or 16/17).
- Fastlock and cycle slip reduction with integrated time-out counter requiring only a single-word write.
- Digital lock detect output and hardware and software power-down control.
- On-chip input frequency doubler.
- Serial data programming through a three-line, high-speed (20-MHz) MICROWIRE interface.
Applications
- Cellular phones and base stations.
- Direct digital modulation applications.
- Satellite and cable TV tuners.
- WLAN standards.
Q & A
- What is the operating frequency range of the LMX2485E RF PLL?
The LMX2485E RF PLL operates from 50 MHz to 3.0 GHz. - What is the typical current consumption of the LMX2485?
The typical current consumption is 5.0 mA. - What is the purpose of the delta-sigma modulator in the LMX2485?
The delta-sigma modulator is used to push fractional spurs to higher frequencies outside the loop bandwidth, improving phase noise and spur performance. - How is the LMX2485 programmed?
The LMX2485 is programmed through a three-line, high-speed (20-MHz) MICROWIRE interface. - What are the key applications of the LMX2485?
Key applications include cellular phones and base stations, direct digital modulation, satellite and cable TV tuners, and WLAN standards. - What is the package type of the LMX2485?
The LMX2485 is available in a 24-lead 4.0 × 4.0 × 0.8 mm WQFN package. - What is the operating temperature range of the LMX2485?
The operating temperature range is -40°C to 85°C. - Does the LMX2485 support power-down control?
Yes, it supports both hardware and software power-down control. - What is the maximum phase detector frequency for the LMX2485?
The maximum phase detector frequency is up to 50 MHz. - Is the LMX2485 suitable for direct digital modulation applications?
Yes, it is highly suitable for direct digital modulation applications due to its fine frequency resolution and fast programming speed.
