Integer-N / Fractional-N PLL Synthesizer

The ADF4155 allows implementation of fractional-N or integer-N phase-locked loop (PLL) frequency synthesizers when used with an external loop filter, external voltage controlled oscillator (VCO), and external reference frequency.

The ADF4155 is for use with external VCO parts up to an 8 GHz operating frequency. The high resolution programmable modulus allows synthesis of exact frequencies with 0 Hz error.

The VCO frequency can be divided by 1, 2, 4, 8, 16, 32, or 64 to allow the user to generate RF output frequencies as low as 7.8125 MHz.

Control of all on-chip registers is through a simple 3-wire interface. The device operates with a nominal power supply of 3.3 V ± 5% and can be powered down when not in use.

The ADF4155 is available in a 24-lead, 4 mm × 4 mm LFCSP package.

APPLICATIONS

* Wireless infrastructure (W-CDMA, TD-SCDMA, WiMAX, GSM, PCS, DCS, DECT)

* Point to point/point to multipoint microwave links

* Test equipment

* Wireless LANs, CATV equipment

* Clock generation

* Input frequency range: 500 MHz to 8000 MHz

* Fractional-N synthesizer and integer-N synthesizer

* Phase frequency detector (PFD) up to 125 MHz

* High resolution 38-bit modulus

* Separate charge pump supply (VP) allows extended tuning voltage in 5 V systems

* Programmable divide by 1, 2, 4, 8, 16, 32, or 64 output