This data sheet introduces the ADF4158, a 6.1 GHz, fractional-N frequency synthesizer with a 25-bit fixed modulus that allows subhertz frequency resolution, frequency and phase modulation capability, sawtooth and triangular waveforms in the frequency domain, parabolic ramp, superimposed FSK ramp, 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, qualified for automotive applications.