The PE3291 is a dual fractional-N FlexiPower phase-lock loop (PLL) IC designed
for frequency synthesis and fabricated on Peregrine's patented UltraCMOS™
process. Each PLL includes a FlexiPowerTM prescaler, phase detector, charge pump
and on-board fractional spur compensation.
The FlexiPower prescalers are supplied power on dedicated pins and can
operate at a substantial power savings at voltages as low as 0.8 volts, while
allowing a 3 volt charge pump supply. For 3 volt only systems, on-chip voltage
regulation may be used to generate the prescaler power supplies.
The prescaler power supply may be provided externally or internally regulated
down from Vdd. In a typical 950 MHz application the total current consumed by
the PLL is 2.1 mA. Operation at reduced current levels provides significant
battery life extension. The PE3291 allows the system designer to minimize power
consumption by controlling the voltage on the prescaler.
PE3291 provides fractional-N division with power-of-two denominator values up
to 32. This allows comparison frequencies up to 32 times the channel spacing,
providing a lower phase noise floor than integer PLLs. The 32/33 RF prescaler
(PLL1) operates up to 1.2 GHz and the 16/17 IF prescaler (PLL2) operates up to
550 MHz. It is offered in a 20-lead TSSOP package.
