LMX2306/LMX2316/LMX2326
PLLatinum
™
Low Power Frequency Synthesizer for RF
Personal Communications
LMX2306 550 MHz
LMX2316 1.2 GHz
LMX2326 2.8 GHz
General Description
The LMX2306/16/26 are monolithic, integrated frequency
synthesizers with prescalers that are designed to be used to
generate a very stable low noise signal for controlling the lo-
cal oscillator of an RF transceiver. They are fabricated using
National’s ABiC V silicon BiCMOS 0.5µ process.
The LMX2306 contains a 8/9 dual modulus prescaler while
the LMX2316 and the LMX2326 have a 32/33 dual modulus
prescaler. The LMX2306/16/26 employ a digital phase
locked loop technique. When combined with a high quality
reference oscillator and loop filter, the LMX2306/16/26 pro-
vide the feedback tuning voltage for a voltage controlled os-
cillator to generate a low phase noise local oscillator signal.
Serial data is transferred into the LMX2306/16/26 via a three
wire interface (Data, Enable, Clock). Supply voltage can
range from 2.3V to 5.5V. The LMX2306/16/26 feature ultra
low current consumption; LMX2306 - 1.7 mA at 3V,
LMX2316 - 2.5 mA at 3V, and LMX2326 - 4.0 mA at 3V.
The LMX2306/16/26 synthesizers are available in a 16-pin
TSSOP surface mount plastic package.
Features
n 2.3V to 5.5V operation
n Ultra low current consumption
n 2.5V V
CC
JEDEC standard compatible
n Programmable or logical power down mode:
—I
CC
= 1 µA typical at 3V
n Dual modulus prescaler:
— LMX2306 8/9
— LMX2316/26 32/33
n Selectable charge pump TRI-STATE
®
mode
n Selectable FastLock
™
mode with timeout counter
n MICROWIRE
™
Interface
n Digital Lock Detect
Applications
n Portable wireless communications (PCS/PCN, cordless)
n Wireless Local Area Networks (WLANs)
n Cable TV tuners (CATV)
n Pagers
n Other wireless communication systems
Functional Block Diagram
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
FastLock
™
, PLLatinum
™
and MICROWIRE
™
are trademarks of National Semiconductor Corporation.
DS100127-1
April 2000
LMX2306/LMX2316/LMX2326 PLLatinum Low Power Frequency Synthesizer for RF Personal
Communications
© 2000 National Semiconductor Corporation DS100127 www.national.com
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