LMX2353 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – PLLatinum™ Fractional N Single 2.5 GHz Frequency Synthesizer

PRELIMINARY
June 1999
LMX2353
PLLatinum^™ Fractional N Single 2.5 GHz Frequency
Synthesizer
General Description
The LMX2353 is a monolithic integrated fractional N fre-
quency synthesizer, designed to be used in a local oscillator
subsystem for a radio transceiver. It is fabricated using Na-
tional’s 0.5µ ABiC V silicon BiCMOS process. The LMX2353
contains dual modulus prescalers along with modulo 15 or
16 fractional compensation circuitry in the N divider. A 16/17
or 32/33 prescale ratio can be selected for the LMX2353. Us-
ing a fractional N phase locked loop technique, the LMX2353
can generate very stable low noise control signals for UHF
and VHF voltage controlled oscillators (VCO’s).
The LMX2353 has a highly flexible 16 level programmable
charge pump supplies output current magnitudes from 100
µA to 1.6 mA. Serial data is transferred into the LMX2353 via
a three wire interface (Data, LE, Clock). Supply voltage can
range from 2.7V to 5.5V. The LMX2353 features very low
current consumption; typically 4.5 mA at 3.0V. The LMX2353
is available in a 16-pin TSSOP or a 16-pad CSP surface
mount plastic package.
Features
n 2.7V – 5.5V operation
n Low Current Consumption
I_CC = 4.5 mA typ @ V_CC = 3.0V
n Programmable or Logical Power Down Mode
I_CC = 5 µA typ @ V_CC = 3.0V
n Modulo 15 or 16 fractional N divider
Supports ratios of 1, 2, 3, 4, 5, 8, 15, or 16
n Programmable charge pump current levels
100 µA to 1.6 mA in 100 µA steps
n Digital Filtered Lock Detect
Applications
n Portable wireless communications (PCS/PCN, cordless)
n Zero blind slot TDMA systems
n Cellular and Cordless telephone systems
n Spread spectrum communication systems (CDMA)
Functional Block Diagram
MICROWIRE™ and PLLatinum™ are trademarks of National Semiconductor Corporation.
TRI-STATE^® is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation DS101124
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