Catalog
High Resolution 6 GHzFractional-N Frequency Synthesizer
Key Features
• RF bandwidth to 6 GHz
• 25-bit fixed modulus allows subhertz frequency resolution
• 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
• Pin compatible with the following frequency synthesizers:
• ADF4110/ADF4111/ADF4112/ADF4113
• ADF4106/ADF4153/ADF4154/ADF4156
• Cycle slip reduction for faster lock times
Description
AI
The ADF4157 is a 6 GHz fractional-N frequency synthesizer with a 25-bit fixed modulus, allowing subhertz frequency resolution at 6 GHz. It consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider. There is a Σ-Δ based fractional interpolator to allow programmable fractional-N division. The INT and FRAC values define an overall N divider, N = INT + (FRAC/225). The ADF4157 features cycle slip reduction circuitry, which leads to faster lock times without the need for modifications to the loop filter.Control of all on-chip registers is via a simple 3-wire interface. 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.ApplicationsSatellite communications terminals, radar equipmentInstrumentation equipmentPersonal mobile radio (PMR)Base stations for mobile radioWireless handsets
