GENERAL DESCRIPTION
The ADF4158 is a 6.1 GHz, fractional-N frequency synthesizer with modulation and waveform generation capability. It contains a 25-bit fixed modulus, allowing subhertz resolution at 6.1 GHz. 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 and FRAC registers define an overall N-divider as N = INT + (FRAC/2²⁵).

FEATURES
RF bandwidth to 6.1 GHz
25-bit fixed modulus allows subhertz frequency resolution
Frequency and phase modulation capability
Sawtooth and triangular waveforms in the frequency domain
Parabolic ramp
Ramp superimposed with FSK
Ramp with 2 different sweep rates
Ramp delay
Ramp frequency readback
Ramp interruption
2.7 V to 3.3 V power supply
Separate VP allows extended tuning voltage
Programmable charge pump currents
3-wire serial interface
Digital lock detect
Power-down mode
Cycle slip reduction for faster lock times
Switched bandwidth fast-lock mode

APPLICATIONS
FMCW radar
Communications test equipment