LMX2370 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – PLLatinum™ Dual Frequency Synthesizer for RF Personal Communications

PRELIMINARY
March 1999
LMX2370/LMX2371/LMX2372
PLLatinum^™ Dual Frequency Synthesizer for RF
Personal Communications
LMX2370 2.5 GHz/1.2 GHz
LMX2371 2.0 GHz/1.2 GHz
LMX2372 1.2 GHz/1.2 GHz
General Description
The LMX237X family of monolithic, integrated dual fre-
quency synthesizers, including prescalers, is designed to be
used as a first and second local oscillator for dual mode or
dual conversion transceivers. It is fabricated using National’s
0.5u ABiCV silicon BiCMOS process. The LMX237X con-
tains two dual modulus prescalers. A 32/33 or a 16/17
prescaler can be selected for the 2.5 GHz and 2.0 GHz RF
synthesizers with the 16/17 prescaler rated for input frequen-
cies below 1.2 GHz. A 16/17 or an 8/9 prescaler can be se-
lected for the 1.2 GHz RF synthesizers with the 8/9 prescaler
rated for input frequencies below 550 MHz. Using a digital
phase locked loop technique, the LMX237X can generate
very stable, low noise control signals for UHF and VHF volt-
age controlled oscillators (VCO’s). Serial data is transferred
into the LMX237X via a 1.8V three wire interface (Data, En-
able, Clock) compatible with low voltage baseband proces-
sors. Supply voltage can range from 2.7V to 5.5V. The
LMX237X family features very low current consumption typi-
cally: LMX2370 - 6.0 mA @ 3V, LMX2371 - 5.0 mA @ 3V,
LMX2372 - 4.0 mA @ 3V.
The LMX237X are available in a 24-pad chip scale (CSP) or
a 20-pin TSSOP surface mount plastic package.
Features
n 2.7V–5.5V operation
n Ultra low current consumption
n Low phase detector noise floor
n Low voltage MICROWIRE™ interface (1.8V up to V_CC)
n Low prescaler values
32/33 @ f_IN ≤ 2.5 GHz
16/17 @ f_IN ≤ 1.2 GHz
8/9 @ f_IN ≤ 550 MHz
n Selectable charge pump current levels
n Selectable FastLock™ mode
n Enhanced ESD protection
n Small 24 pad chip scale package (3.5 x 4.5 x 1.0 mm)
Applications
n Portable wireless communications (PCS/PCN, cordless)
n Dual mode cellular telephone systems
n Spread spectrum communication systems (CDMA)
n Cable TV tuners (CATV)
Functional Block Diagram
FastLock™, PLLatinum™ and MICROWIRE™ are trademarks of National Semiconductor Corporation.
TRI-STATE^® is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation DS101026
DS101026-1
www.national.com