VddRF5
Phase
Comp
FinIF
Charge
Pump
CPoutIF
Ftest/LD
MUX
Ftest/LD
IF
LD
Phase
Comp
8/9
or
16/17
Prescaler
B Counter
IF N Divider
A Counter
FLoutRF
VddIF2
VddIF1
RF N Divider
GND
GND
GND
FinRF
FinRF*
16/17/20/21
or
32/33/36/37
Prescaler
C Counter
6'
Compensation
A Counter
B Counter
RF N Divider
ENOSC
OSCout
OSCin
VddRF4
VddRF3
VddRF2
VddRF1
IF R
Divider
RF R
Divider
1X / 2X
RF LD
Charge
Pump
CPoutRF
RF Fastlock
MICROWIRE
Interface
CLK
LE
DATA
CE
LMX2486
www.ti.com
SNAS324 –JANUARY 2006
LMX2486 1.0 GHz - 4.5 GHz High Performance Delta-Sigma Low Power Dual PLLatinum™
Frequency Synthesizers with 3.0 GHz Integer PLL
Check for Samples: LMX2486
1
FEATURES
DESCRIPTION
The LMX2486 is a low power, high performance
23
• Quadruple Modulus Prescalers for Lower
delta-sigma fractional-N PLL with an auxiliary integer-
Divide Ratios
N PLL. The device is fabricated using TI’s advanced
– RF PLL: 16/17/20/21 or 32/33/36/37
process.
– IF PLL: 8/9 or 16/17
With delta-sigma architecture, fractional spurs at
• Advanced Delta Sigma Fractional
lower offset frequencies are pushed to higher
Compensation
frequencies outside the loop bandwidth. The ability to
push close in spur and phase noise energy to higher
– 12 Bit or 22 Bit Selectable fractional
frequencies is a direct function of the modulator
Modulus
order. Unlike analog compensation, the digital
– Up to 4th order Programmable Delta-Sigma
feedback technique used in the LMX2486 is highly
Modulator
resistant to changes in temperature and variations in
• Features for Improved Lock Times and
wafer processing. The LMX2486 delta-sigma
modulator is programmable up to fourth order, which
Programming
allows the designer to select the optimum modulator
– Fastlock / Cycle Slip Reduction
order to fit the phase noise, spur, and lock time
– Integrated Time-out Counter
requirements of the system.
– Single Word Write to Change Frequencies
Serial data for programming the LMX2486 is
with Fastlock
transferred via a three line high speed (20 MHz)
• Wide Operating Range
MICROWIRE interface. The LMX2486 offers fine
frequency resolution, low spurs, fast programming
– LMX2486 RF PLL: 1.0 GHz to 4.5 GHz
speed, and a single word write to change the
• Useful Features
frequency. This makes it ideal for direct digital
– Digital Lock Detect Output
modulation applications, where the N counter is
directly modulated with information. The LMX2486 is
– Hardware and Software Power-down
available in a 24 lead 4.0 X 4.0 X 0.8 mm WQFN
Control
package.
– On-chip Crystal Reference Frequency
Doubler.
Functional Block Diagram
– RF Phase Comparison Frequency up to 50
MHz
– 2.5 to 3.6 Volt Operation with I
CC
= 8.5 mA
at 3.0 V
APPLICATIONS
• Cellular Phones and Base Stations
– CDMA, WCDMA, GSM/GPRS, TDMA, EDGE,
PDC
• Direct Digital Modulation Applications
• Satellite and Cable TV Tuners
• WLAN Standards
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2PLLatinum is a trademark of Texas Instruments.
3All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2006, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
