Overview
The LMX2581SQX/NOPB is a wideband frequency synthesizer produced by Texas Instruments. This device integrates a delta-sigma fractional N PLL, multiple core VCO, programmable output dividers, and two differential output buffers. It is designed to provide high performance and flexibility in various frequency synthesis applications. The synthesizer operates on a single 3.3 V supply and is packaged in a 32-pin 5.0 mm × 5.0 mm WQFN package.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Output Frequency | 50 | - | 3760 | MHz |
| Input Clock Frequency | 5 | - | 900 | MHz |
| Phase Detector Frequency | - | - | 200 | MHz |
| VCO Frequency Range | 1880 | - | 3760 | MHz |
| Normalized PLL Phase Noise | -229 | - | - | dBc/Hz |
| Normalized PLL 1/f Noise | -120.8 | - | - | dBc/Hz |
| VCO Phase Noise @ 1 MHz offset | -137 | - | - | dBc/Hz |
| RMS Jitter in Integer Mode | - | 100 | - | fs |
| Supply Voltage | 3.15 | 3.3 | 3.45 | V |
| Operating Temperature Range | -40 | - | 85 | °C |
Key Features
- Supports fractional and integer modes
- Programmable fractional modulator order and denominator
- Programmable output power up to +12 dBm
- Programmable 32-level charge pump current
- Option to use an external VCO
- Digital lock detect and lock detection
- 3-wire serial interface and readback feature
- Single supply voltage from 3.15 V to 3.45 V
- Supports logic levels down to 1.6 V
- Integrated low noise LDOs for superior noise immunity
- Power down, Fastlock, auto mute, and other convenient features
Applications
- Wireless Infrastructure (UMTS, LTE, WiMax, Multi-Standard Base Stations)
- Broadband Wireless
- Test and Measurement
- Clock Generation
Q & A
- What is the output frequency range of the LMX2581?
The output frequency range of the LMX2581 is from 50 MHz to 3760 MHz.
- What is the input clock frequency range of the LMX2581?
The input clock frequency range of the LMX2581 is up to 900 MHz.
- What is the phase noise performance of the LMX2581?
The LMX2581 has a normalized PLL phase noise of -229 dBc/Hz and a VCO phase noise of -137 dBc/Hz at 1 MHz offset.
- Can the LMX2581 operate in both fractional and integer modes?
Yes, the LMX2581 supports both fractional and integer modes.
- What is the supply voltage range for the LMX2581?
The supply voltage range for the LMX2581 is from 3.15 V to 3.45 V.
- Does the LMX2581 have an option to use an external VCO?
Yes, the LMX2581 has an option to use an external VCO.
- What is the package type and size of the LMX2581?
The LMX2581 comes in a 32-pin 5.0 mm × 5.0 mm WQFN package.
- What are some of the key applications of the LMX2581?
The LMX2581 is used in wireless infrastructure, broadband wireless, test and measurement, and clock generation.
- Does the LMX2581 have a digital lock detect feature?
Yes, the LMX2581 includes a digital lock detect and lock detection feature.
- How is the LMX2581 programmed?
The LMX2581 can be programmed through a 3-wire serial interface and also has a readback feature.
