Model Si4133 is a monolithic dual-band frequency synthesizer from Silicon Laboratories with integrated voltage-controlled oscillators (VCOs) for wireless applications through 1.8 GHz. The first synthesizer tunes from 900 to 1800 MHz while the second synthesizer tunes from 750 to 1500 MHz. The unit includes an intermediate-frequency (IF) synthesizer with a range of 62.5 to 1000 MHz. The phase noise for the first synthesizer is -132 dBc/Hz offset 1 MHz from the carrier and the phase noise for the second synthesizer is typically -134 dBc/Hz offset 1 MHz from the carrier. Harmonic levels are typically -26 dBc while spurious content is typically -65 dBc. The monolithic device includes three VCOs, loop filters, reference source, and VCO dividers. It is programmable by means of a three-wire interface. The synthesizer typically draws 18 mA current from supplies of +2.7 to +3.6 VDC and runs on standby current of 1 microampere. It is lead-free and RoHS compliant.