SKY72302-21 Spur-Free, 6.1 GHz Dual Fractional-N Frequency Synthesizer

SKYWORKS SKY72302-21 direct digital modulation fractional-N frequency synthesizer provides ultra-fine frequency resolution, fast switching speed, and low phase-noise performance. This synthesizer is a key building block for high-performance radio system designs that require low power and fine step size. The ultra-fine step size of less than 400 Hz allows this synthesizer to be used in very narrowband wireless applications. With proper temperature sensing or through control channels, the synthesizer’s fine step size can compensate for crystal oscillator or Intermediate Frequency (IF) filter drift. As a result, crystal oscillators or crystals can replace temperature-compensated or ovenized crystal oscillators, reducing parts count and associated component cost. The device’s fine step size can also be used for Doppler shift corrections. The SKY72302-21 has a phase noise floor of –80 dBc/Hz up to 6.1 GHz operation as measured inside the loop bandwidth. This is permitted by the on-chip low noise dividers and low divide ratios provided by the device’s high fractionality. Reference crystals or oscillators up to 50 MHz can be used with the SKY72302-21. The crystal frequency is divided down by independent programmable dividers (1 to 32) for the main and auxiliary synthesizers. The phase detectors can operate at a maximum speed of 25 MHz, which allows better phase noise due to the lower division value. With a high reference frequency, the loop bandwidths can also be increased. Larger loop bandwidths improve the settling times and reduce in-band phase noise. Therefore, typical switching times of less than 100 􀁐s can be achieved. The lower in-band phase noise also permits the use of lower cost Voltage Controlled Oscillators (VCOs) in customer applications.

技术特性

Spur-free operation
6.1 GHz maximum operating frequency
1000 MHz maximum auxiliary synthesizer
Ultra-fine step size, 400 Hz or less
High internal reference frequency enables large loop bandwidth
implementations
Very fast switching speed (e.g., below 100 􀁐s)
Phase noise to –80 dBc/Hz inside loop filter bandwidth
@ 6100 MHz
Software programmable power-down modes
High speed serial interface up to 100 Mbps
Three-wire programming
Programmable division ratios on reference frequency
Phase detectors with programmable gains to provide a
programmable loop bandwidth
Frequency power steering further enhances rapid acquisition
time
On-chip crystal oscillator
Frequency adjust for temperature compensation
Direct digital modulation

订购信息 Ordering Information

SKY72302-21

应用领域 APPLICATION

General purpose RF systems
2.5G and 3G wireless infrastructures
Broadband wireless access
Low bit rate wireless telemetry
Wireless Local Loop (WLL)
Instrumentation

功能框图 Functional Block Diagram

应用技术支持与电子电路设计开发资源下载	版本信息	大小
SKY72302-21 数据资料DataSheet下载:pdf	Rev.V2	2 页