The Si4133G features a proprietary self-tuning architecture that does not require VCO modules and provides the ability to achieve the fast settling times required for GPRS. RF synthesis is performed in two bands, 900 MHz to 1.8 GHz and 750 MHz to 1.5 GHz, as well as IF synthesis from 62.5 MHz to 1.0 GHz.
The low settling time of 150 μs is maintained even when hopping from one end of the synthesizable tuning range to the other, allowing Si4133G-based products to easily meet requirements for GPRS classes 1 through 12. The unique integer-N architecture of the synthesizer provides these settling times without generating additional spurious sidebands associated with fractional-N synthesizers. The synthesizer comes standard in a low-profile, small outline, 24-pin package (TSSOP) and will be available in 28-lead chip scale package.