LMX2364 Datasheet, PDF (1/39 Pages) National Semiconductor (TI) – 2.6 GHz PLLatinum Fractional RF Frequency Synthesizer with 850 MHz Integer IF Frequency Synthesizer

July 2003
LMX2364
2.6 GHz PLLatinum Fractional RF Frequency Synthesizer
with 850 MHz Integer IF Frequency Synthesizer
General Description
The LMX2364 integrates a high performance 2.6 GHz frac-
tional frequency synthesizer with a 850 MHz low power
Integer-N frequency synthesizer. Designed for use in a local
oscillator subsystem of a radio transceiver, the LMX2364
generates very stable, low noise control signals for UHF and
VHF voltage controlled oscillators. It is fabricated using Na-
tional’s high performance BiCMOS process.
The RF Synthesizer supports both fractional and integer
modes. The N counter contains a selectable, quadruple
modulus prescaler and can support fractional denominators
from 1 to 128. A flexible, 4 level programmable charge pump
supplies output current magnitudes ranging from 1 mA to 16
mA. Only a single word write is required to power up and
tune the synthesizer to a new frequency.
High performance FastLock™ technology makes the
LMX2364 an excellent choice for applications requiring ag-
gressive lock time while maintaining excellent phase noise
and spurious performance. The combination of the improved
FastLock circuitry, the enhanced fractional compensation
engine, and the programmable charge pump architecture
gives the designer maximum freedom to optimize the perfor-
mance of the synthesizer for the target application. Inte-
grated timeout counters greatly simplify the programming
aspects of FastLock. These timeout counters reduce the
demands on the microcontroller by automatically disengag-
ing FastLock after a perscribed number of reference cycles
of the phase detector.
The IF synthesizer includes a fixed 8/9 dual modulus pres-
caler, a two level programmable charge pump, and dedi-
cated FastLock circuitry with an integrated timeout counter.
The LMX2364 offers many performance enhancements over
the LMX2354. Improvements in the fractional compensation
make the spurs on the LMX2364 approximately 6 dB better
in a typical application. The higher and more flexible frac-
tional modulus combined with the higher charge pump cur-
rents result in phase noise improvements on the order of 10
dB. The cycle slip reduction circuitry of the LMX2364 is both
easy to use and effective in reducing cycle slipping and
allows one to use very high phase detector frequencies
without degrading lock times.
Serial data is transferred to the device via a three-wire
interface (DATA, LE, CLK). The low voltage logic interface
allows direct connection to 1.8 Volt and 3.0 Volt devices.
Supply voltages from 2.7V to 5.5V are supported. Indepen-
dent charge pump supplies for each synthesizer allows the
designer to optimize the bias level for the selected VCO. The
LMX2364 consumes 5.0 mA (typical) of current in integer
mode and 7.2 mA (typical) in fractional mode. The LMX2364
is available in a 24 Pin Ultra Thin CSP package and 24 Pin
TSSOP Package.
Features
n RF Synthesizer supports both Fractional and Integer
Operating Modes
n Pin Compatible upgrade for LMX2354
n 2.7V to 5.5V operation
n Pin and programmable power down
n Fractional N divider supports fractional denominators
ranging from 1 through 128
n Supports Integer Mode Operation
n Programmable charge pump current levels
RF: 4 level, 1 – 16 mA
IF: 2 level, 100/800 uA
n FastLock Technology with integrated timeout counters
n Digital filtered & analog lock detect output
n FastLock Glitch Reduction Technology
n Enhanced Low Noise Fractional Compensation Engine
n Low voltage programming interface allows direct
connection to 1.8V logic
Applications
n Digital Cellular
n GPRS
n IS-136
n GAIT
n PDC
n EDGE
n CDMA
n Zero blind slot TDMA systems
n Cable TV Tuners (CATV)
FastLock™ is a trademark of National Semiconductor Corporation.
TRI-STATE^® is a registered trademark of National Semiconductor Corporation.
© 2003 National Semiconductor Corporation DS200506
www.national.com