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