LMX2335/LMX2336/LMX2337
PLLatinum™ Dual Frequency Synthesizer for RF
Personal Communications
LMX2335
LMX2336
LMX2337
1.1 GHz/1.1 GHz
2.0 GHz/1.1 GHz
550 MHz/550 MHz
General Description
The LMX2335, LMX2336 and LMX2337 are monolithic, integrated dual frequency synthesizers, including two high frequency prescalers, and are designed for applications requiring two RF phase-lock loops. They are fabricated using
National’s ABiC IV silicon BiCMOS process.
The LMX2335/36/37 contains two dual modulus prescalers.
A 64/65 or a 128/129 prescaler can be selected for each RF
synthesizer. A second reference divider chain is included in
the IC for improved system noise. LMX2335/36/37, which
employ a digital phase locked loop technique, combined with
a high quality reference oscillator and loop filters, provide the
tuning voltages for voltage controlled oscillators to generate
very stable low noise RF local oscillator signals.
Serial data is transferred into the LMX2335/36/37 via a three
wire interface (Data, Enable, Clock). Supply voltage can
range from 2.7V to 5.5V. The LMX2335/36/37 feature very
low current consumption; LMX2335/37 −10 mA at 3V,
LMX2336 −13 mA at 3V. The LMX2335/37 are available in
both a JEDEC SO and TSSOP 16-pin surface mount plastic
package. The LMX2336 is available in a TSSOP 20-pin surface mount plastic package.
Features
n 2.7V to 5.5V operation
n Low current consumption
n Selectable powerdown mode:
ICC = 1 µA (typ)
n Dual modulus prescaler: 64/65 or 128/129
n Selectable charge pump TRI-STATE ® mode
n Selectable charge pump current levels
n Selectable FastLock™ mode
Applications
n Cellular telephone systems (AMPS, ETACS, RCR-27)
n Cordless telephone systems (DECT, ISM, PHS, CT-1+)
n Personal Communication Systems
(DCS-1800, PCN-1900)
n Dual Mode PCS phones
n CATV
n Other wireless communication systems
Functional Block Diagram
DS012332-1
TRI-STATE ® is a registered trademark of National Semiconductor Corporation.
Fastlock™, MICROWIRE™ and PLLatinum™ are trademarks of National Semiconductor Corporation.
© 2000 National Semiconductor Corporation
DS012332
www.national.com
LMX2335/LMX2336/LMX2337 PLLatinum Dual Frequency Synthesizer for RF Personal
Communications
September 1996
