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參數資料
| 型號： | LMX2485SQX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | XO, clock |
| 英文描述： | 50 MHz - 3.0 GHz High Performance Delta-Sigma Low Power Dual PLLatinum⑩ Frequency Synthesizers with 800 MHz Integer PLL |
| 中文描述： | PLL FREQUENCY SYNTHESIZER, 3000 MHz, PQCC24 |
| 封裝： | 4 X 4 MM, 0.8 MM, PLASTIC, LLP-24 |
| 文件頁數： | 1/37頁 |
| 文件大小： | 861K |
| 代理商： | LMX2485SQX |
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LMX2485/LMX2485E
50 MHz - 3.0 GHz High Performance Delta-Sigma Low
Power Dual PLLatinum
Frequency Synthesizers with
800 MHz Integer PLL
General Description
The LMX2485 is a low power, high performance delta-sigma
fractional-N PLL with an auxiliary integer-N PLL. The device
is fabricated using National Semiconductor’s advanced pro-
cess.
With delta-sigma architecture, fractional spurs at lower offset
frequencies are pushed to higher frequencies outside the
loop bandwidth. The ability to push close in spur and phase
noise energy to higher frequencies is a direct function of the
modulator order. Unlike analog compensation, the digital
feedback technique used in the LMX2485 is highly resistant
to changes in temperature and variations in wafer process-
ing. The LMX2485 delta-sigma modulator is programmable
up to fourth order, which allows the designer to select the
optimum modulator order to fit the phase noise, spur, and
lock time requirements of the system.
Serial data for programming the LMX2485 is transferred via
a three line high speed (20 MHz) MICROWIRE interface.
The LMX2485 offers fine frequency resolution, low spurs,
fast programming speed, and a single word write to change
the frequency. This makes it ideal for direct digital modula-
tion applications, where the N counter is directly modulated
with information. The LMX2485 is available in a 24 lead
4.0 X 4.0 X 0.8 mm LLP package.
Applications
n
Cellular phones and base stations
CDMA, WCDMA, GSM/GPRS, TDMA, EDGE, PDC
n
Direct digital modulation applications
n
Satellite and cable TV tuners
n
WLAN Standards
Features
Quadruple Modulus Prescalers for Lower Divide Ratios
n
RF PLL:
8/9/12/13 or 16/17/20/21
n
IF PLL:
8/9 or 16/17
Advanced Delta Sigma Fractional Compensation
n
12 bit or 22 bit selectable fractional modulus
n
Up to 4th order programmable delta-sigma modulator
Features for Improved Lock Times and Programming
n
Fastlock / Cycle slip reduction
n
Integrated time-out counter
n
Single word write to change frequencies with Fastlock
Wide Operating Range
n
LMX2485 RF PLL: 500 MHz to 3.0 GHz
n
LMX2485E RF PLL: 50 MHz to 3.0 GHz
Useful Features
n
Digital lock detect output
n
Hardware and software power-down control
n
On-chip crystal reference frequency doubler.
n
RF phase comparison frequency up to 50 MHz
n
2.5 to 3.6 volt operation with I
CC
= 5.0 mA at 3.0 V
Functional Block Diagram
20087701
PLLatinum
is a trademark of National Semiconductor Corporation.
February 2006
L
S
2006 National Semiconductor Corporation
DS200877
www.national.com
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LMX2485SQX/NOPB | 功能描述:鎖相環 - PLL RoHS:否 制造商:Silicon Labs 類型:PLL Clock Multiplier 電路數量:1 最大輸入頻率:710 MHz 最小輸入頻率:0.002 MHz 輸出頻率范圍:0.002 MHz to 808 MHz 電源電壓-最大:3.63 V 電源電壓-最小:1.71 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:QFN-36 封裝:Tray |
| LMX2486 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:1.0 GHz - 4.5 GHz High Performance Delta-Sigma Low Power Dual PLLatinum TM Frequency Synthesizers with 3.0 GHz Integer PLL |
| LMX2486EVAL | 功能描述:時鐘和定時器開發工具 LMX2486 EVAL BOARD RoHS:否 制造商:Texas Instruments 產品:Evaluation Modules 類型:Clock Conditioners 工具用于評估:LMK04100B 頻率:122.8 MHz 工作電源電壓:3.3 V |
| LMX2486SQ | 制造商:Texas Instruments 功能描述:PLL Frequency Synthesizer Dual 5MHz to 4500MHz 24-Pin LLP EP T/R |
| LMX2486SQ/NOPB | 功能描述:鎖相環 - PLL RoHS:否 制造商:Silicon Labs 類型:PLL Clock Multiplier 電路數量:1 最大輸入頻率:710 MHz 最小輸入頻率:0.002 MHz 輸出頻率范圍:0.002 MHz to 808 MHz 電源電壓-最大:3.63 V 電源電壓-最小:1.71 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:QFN-36 封裝:Tray |
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