GENERAL DESCRIPTION
The ADF4156 is a 6 GHz 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. There is a sigma-delta (Σ-Δ) based fractional interpolator to allow programmable fractional-N division. The INT, FRAC, and MOD registers define an overall N divider (N = (INT + (FRAC/MOD))). The RF output phase is programmable for applications that require a particular phase relationship between the output and the reference. The ADF4156 also features cycle slip reduction circuitry leading to faster lock times without the
need for modifications to the loop filter.

FEATURES
RF bandwidth to 6 GHz
2.7 V to 3.3 V power supply
Separate VP allows extended tuning voltage
Programmable fractional modulus
Programmable charge pump currents
3-wire serial interface
Digital lock detect
Power-down mode
Pin compatible with
ADF4110/ADF4111/ADF4112/ADF4113/ADF4106/
ADF4153 and ADF4154 frequency synthesizers
Programmable RF output phase
Loop filter design possible with ADISimPLL
Cycle slip reduction for faster lock times

APPLICATIONS
CATV equipment
Base stations for mobile radio (WiMAX, GSM, PCS, DCS,
SuperCell 3G, CDMA, WCDMA)
Wireless handsets (GSM, PCS, DCS, CDMA, WCDMA)
Wireless LANs, PMR
Communications test equipment