Analog Devices, Inc. (ADI) has released two new PLL synthesizers-- ADF4151 and ADF4196--for applications such as communications infrastructure base-stations, pulse and Doppler radar applications, test and instrumentation equipment, microwave point-to-point systems, PMR (professional mobile radio), VSATs (very small aperture terminals) and aerospace systems.
With an RF bandwidth of 3.5 GHz, the ADF4151 allows implementation of a Fractional-N or Integer-N PLL synthesizer. It consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider and is pin-and software-compatible with ADI’s widely-used ADF4350 4.4 GHz PLL. When these two PLLs are used together, the ADF4151 facilitates the use of an external voltage controlled oscillator (VCO) and improves phase noise without significant board revisions.
The ADF4151 has a 3 to 3.6 V power supply, 1.8 V logic compatibility, and a separate charge pump supply that extends tuning voltage (up to 5 V) in 3 V systems. It also includes a programmable dual-modulus prescaler of 4/5 or 8/9, programmable RF output phase and a 3-wire serial interface The company claims the ADF4196 is an ultra-fast settling 6 GHz fractional-N PLL specifically designed to meet the GSM/EDGE lock time requirements for communications infrastructure and pulse Doppler radar applications. When used in conjunction with an external loop filter and VCO, the ADF4196 PLL can achieve lock times of less than 5 µs. It consists of a low noise, digital phase frequency detector (PFD) and a precision differential charge pump. The ADF4196 features frequency hop across GSM band in 5 µs with phase settled within 20 µs, 1? rms phase error at 4 GHz RF output, digitally programmable output phase and a 3-wire serial interface. It also has on-chip, low noise differential amplifier and phase noise figure of merit: -216 dBc/Hz.
The ADF4151 and ADF4196 PLLs are supported by a new version of ADIsimPLL,™ a synthesizer design and simulation tool. A DIsimPLL Version 3.41 supports ADI’s latest PLLs and includes several functionality enhancements. The free development tool can be downloaded here.
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