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ADI offers two PLL synthesizers for wireless apps

Posted: 11 Jun 2004 ?? ?Print Version ?Bookmark and Share

Keywords:analog devices? pll synthesizer? phase-locked loop synthesizer? adf4007? adf4154?

Analog Devices Inc. (ADI) has developed two PLL (phase-locked loop) synthesizers for the upconversion and downconversion of RF signals in wireless applications.

"Customers are continually seeking ways to improve performance while reducing system costs," said Christian Kermarrec, VP for RF and wireless systems. As a response, the company released the ADF4007 and ADF4154 PLL synthesizers.

The ADF4007 is a fixed frequency, low noise Integer-N PLL synthesizer that delivers one of the industry's highest frequency of operation at 7.5GHz. Designed for cellular base stations and satellite radio link applications, it has the capability of operating to 7.5GHz on the RF side and 120MHz at the PFD (phase frequency detector). This PLL synthesizer consists of a low noise digital PFD, a precision charge pump, and a divider/prescaler. The divider/ prescaler value can be set by two external control pins to one of four values (8, 16, 32, or 64), with the reference divider permanently set to 2, allowing an external reference input frequency of up to 240MHz.

The ADF4154 is a Fractional-N PLL synthesizer. Claimed by the company to offer the best phase noise performance of -106dBc/Hz under GSM1800 conditions, this synthesizer comes with a fast locking feature that improves frequency and phase settling times and a programmable modulus that can accommodate multiple system reference frequencies. According to ADI, this allows greater design flexibility in meeting the overall system noise targets.

The ADF4154 is a 500MHz to 4GHz fractional-N frequency synthesizer operating over the 2.7V to 3.3V range. A separate Vp (Charge pump supply) allows extended tuning voltage. Features include programmable charge pump currents and programmable dual modulus at prescalar 4/5, 8/9 with digital lock detect and power-down mode. Software optimization of phase noise or spurious noise is facilitated. The ADF4154 is pin compatible with the ADF4153 and all ADI ADF41xx Integer-N PLLs.

The ADF4007 is offered in a 20-pin LFCSP and is priced at $2.78 each, and the ADF4154 is housed in a 16-pin TSSOP and 20-pin LFCSP for $2.93 per unit. Both pricing are for 10,000-unit quantities.

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