Product Specification
PE3291
Product Description
The PE3291 is a dual fractional-N FlexiPower
TM
phase-lock loop
(PLL) IC designed for frequency synthesis. Each PLL includes
a FlexiPower
TM
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.
Figure 1 illustrates the implementation of the FlexiPower
technology. The prescaler power supply may be provided
externally or internally regulated down from V
DD
. 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. For additional operating speeds
and current consumptions refer to Figures 5 and 6.
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 1200 MHz and the 16/17 IF
prescaler (PLL2) operates up to 550 MHz.
The PE3291 Phase Locked-Loop is manufactured on
Peregrine’s UltraCMOS™ process, a patented variation of
silicon-on-insulator (SOI) technology on a sapphire substrate,
offering the performance of GaAs with the economy and
integration of conventional CMOS.
1200 MHz / 550 MHz Dual
Fractional-N FlexiPower™ PLL
for Frequency Synthesis
Features
•
Ultra-Low Power via FlexiPower
variable supply voltages
•
Modulo-32 fractional-N main counters
•
On-board fractional spur compensation:
No tuning required, stable over
temperature
•
Improved phase noise compared to
integer-N architectures
Applications
•
CDMA handsets
•
CDMA base stations
•
Analog Cordless phones
•
One and two way pagers
Figure 1:
FlexiPower technology enables
the prescaler to operate at voltages down to
0.8 volts. This significantly reduces the total
power.
To Loop Filter
3 Volts
0.8
3 Volts
Ref.
Input
Phase Comparator
and
Charge pump
Regulator
Low
Speed Counters
Prescaler
PE3291
Document No. 70-0009-04
│
www.psemi.com
©2005 Peregrine Semiconductor Corp. All rights reserved.
Page 1 of 15
PEREGRINE [ PEREGRINE SEMICONDUCTOR CORP. ]
