Dual, Integer-N 1.1 GHz/2.0 GHz PLL

The ADF420x family of dual Frequency Synthesizers are used to implement local Oscillators in the upconversion and down- conversion sections of Wireless receivers and transmitters. Each synthesizer consists of a low noise, digital, phase frequency detector (PFD); a precision charge pump; a programmable reference divider; programmable A and B counters; and a dual modulus prescaler (P/P + 1). The A (6-bit) and B (11-bit) Counters in conjunction with the dual modulus prescaler (P/P + 1), implement an N divider (N = BP + A). In addition, the 14-bit reference Counter (R counter) allows selectable REFIN frequencies at the PFD input. The on-chip Oscillator circuitry allows the reference input to be derived from crystal Oscillators A complete phase-locked loop (PLL) CAN be implemented if the synthesizers are used with an external loop Filter and voltage controlled Oscillators (VCOs). By Analog Devices, Inc.