详细描述
The RF2057 is a low power, high performance, wideband RF frequency conversion chip with integrated local oscillator (LO) generation and a pair of RF mixers. The RF synthesizer includes an integrated fractional-N phase locked loop with voltage controlled oscillator (VCO) and dividers to produce a low-phase noise LO signal with a very fine frequency resolution. The buffered LO output drives the built-in RF mixers which convert the signal into the required frequency band. The mixer bias current can be programmed dependent on the required performance and available supply current. The VCO has been designed to cover the frequency range from 1900 MHz to 2400 MHz. The LO dividers can be selected to divide the VCO output frequency by two or four to give lower LO frequencies. The RF mixers are very broad band and operate from 30 MHz to 2500 MHz at the input and output, enabling both up and down conversion. An external crystal of between 10 MHz and 52 MHz or an external reference source of between 10 MHz and 104 MHz can be used with the RF2057 to accommodate a variety of reference frequency options.
The full duplex mode of operation, with well over 60 dB of isolation between mixers, makes the RF2057 ideal for repeater applications.
All on-chip registers are controlled through a simple three-wire serial interface. The RF2057 is designed for 2.7 V to 3.6 V operation for compatibility with portable, battery powered devices. It is available in a plastic 32-pin, 5 mm x 5 mm QFN package
特点
1900 MHz to 2400 MHz VCO Frequency Range
30 MHz to 2.5 GHz Mixer Frequency Range
Fractional-N Synthesizer
Low Phase Noise VCO
On-Chip Crystal-Sustaining Circuit With Programmable Loading Capacitors
Two High-Linearity RF Mixers
Integrated LO Buffers and Dividers
Mixer Input IP3 +18 dBm
Mixer Bias Adjustable for Low Power Operation
Full Duplex Mode
2.7 V to 3.6 V Power Supply
Low Current Consumption 60 mA to 80 mA at 3 V
3-Wire Serial Interface