LMX2505 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – PLLatinu Dual Frequency Synthesizer System with Integrated VCOs

April 2004
LMX2505
PLLatinum^™ Dual Frequency Synthesizer System
with Integrated VCOs
General Description
LMX2505 is a highly integrated, high performance, low
power frequency synthesizer system optimized for dual-
band Japan PDC mobile handsets. Using a proprietary digi-
tal phase locked loop technique, LMX2505 generates very
stable, low noise local oscillator signals for up and down
conversion in wireless communications devices.
LMX2505 includes dual voltage controlled oscillators (VCOs)
for the upper and lower Japan PDC frequency bands, a loop
filter, and a fractional-N RF PLL based on a delta sigma
modulator. In concert these blocks form a closed loop RF
synthesizer system. The RF synthesizer system supports
two frequency bands: PDC1500 and PDC800.
Serial data is transferred to the device via a three-wire
MICROWIRE interface (DATA, LE, CLK).
Operating supply voltage ranges from 2.5 V to 3.3 V.
LMX2505 features low current consumption: 10 mA at 2.8 V
when operating in the PDC800 mode.
LMX2505 is available in a 28-pin leadless leadframe pack-
age (LLP).
Features
n Small Size
5.0 mm X 5.0 mm X 0.75 mm 28-Pin LLP Package
n RF Synthesizer System
Two Integrated VCOs
Integrated Loop Filter
Low Spurious, Low Phase Noise Fractional-N RF PLL
Based on 10-Bit Delta Sigma Modulator
Frequency Resolution Down to 20 kHz
n Supports Various Reference Frequencies
12.6/14.4/25.2/26.0 MHz
n Fast Lock Time: 300 µs
n Low Current Consumption
10 mA at 2.8 V in PDC800 Mode
n 2.5 V to 3.3 V Operation
n Digital Filtered Lock Detect Output
n Hardware and Software Power Down Control
Applications
n Japan PDC Systems at 800 MHz and 1500 MHz
Frequency Bands.
Functional Block Diagram
FastLock™ is a trademark of National Semiconductor Corporation.
TRI-STATE^® is a registered trademark of National Semiconductor Corporation.
PLLatinum™ is a trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS200671
20067107
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