Fractional-N Frequency Synthesizer

The ADF4153A is a fractional-N frequency synthesizer that implements local oscillators in the upconversion and downconversion sections of wireless receivers and transmitters. It consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider. A sigma-delta (Σ-Δ) based fractional interpolator allows programmable fractional-N division. The INT, FRAC, and MOD registers define an overall N divider (N = (INT + (FRAC/MOD))). In addition, the 4-bit reference counter (R counter) allows selectable REFIN frequencies at the PFD input. A complete phase-locked loop (PLL) can be implemented if the synthesizer is used with an external loop filter and a voltage controlled oscillator (VCO).

A simple 3-wire interface controls all on-chip registers. The device operates with a power supply ranging from 2.7 V to 3.3 V and can be powered down when not in use.

Applications

* CATV equipment

* Base stations for mobile radio (GSM, PCS, DCS, WiMAX,

SuperCell 3G, CDMA, W-CDMA)

* Wireless handsets (GSM, PCS, DCS, CDMA, W-CDMA)

* Wireless LANs, PMR

* Communications test equipment

* RF bandwidth to 4 GHz

* 2.7 V to 3.3 V power supply

* Separate VP allows extended tuning voltage

* Programmable fractional modulus

* Programmable charge pump current

* 3-wire serial interface

* Analog and digital lock detect

* Power-down mode

* Pin-compatible with ADF4106/ADF4110/ADF4111/ADF4112/ ADF4113 and ADF4153

* Consistent RF output phase

* Loop filter design possible with ADIsimPLL