Features Quadruple Modulus Prescalers for Lower Divide Ratios RF PLL: 8/9/12/13 or 16/17/20/21 IF PLL: 8/9 or 16/17 Advanced Delta Sigma Fractional Compensation 12 bit or 22 bit selectable fractional modulus Up to 4th order programmable delta-sigma modulator Features for Improved Lock Times and Programming Fastlock / Cycle slip reduction Integrated time-out counter Single word write to change frequencies with Fastlock Wide Operating Range LMX2485 RF PLL: 500 MHz to 3.0 GHz LMX2485E RF PLL: 50 MHz to 3.0 GHz Useful Features Digital lock detect output Hardware and software power-down control On-chip crystal reference frequency doubler. RF phase comparison frequency up to 50 MHz 2.5 to 3.6 volt operation with ICC = 5.0 mA at 3.0 V 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 process. 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 processing. 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 modulation 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 Cellular phones and base stations CDMA, WCDMA, GSM/GPRS, TDMA, EDGE, PDC Direct digital modulation applications Satellite and cable TV tuners WLAN Standards

LMX2485 WEBENCH® Design/Analyze/Build It RF-Side PLL Design Options Min Output Freq MHz >= 500 help Max Output Freq MHz <= 3000 help Channel Spacing KHz > 0 help AUX-Side PLL Design Options Min Output Freq MHz >= 75 help Max Output Freq MHz <= 800 help Channel Spacing KHz > 0 help Global Design Options Crystal Frequency MHz > 0 help Max Supply V > 0 help What is WEBENCH®? Also Recommended LMX2485E▲ Extended Minimum Operating Frequency Down To 50 MHz. LMX2486▲ 4.5 GHz Maximum Operating Frequency. LMX2487▲ 6.0 GHz Maximum Operating Frequency. LMX2487E▲ 7.5 GHz Maximum Operating Frequency.

	Block Diagram click for larger image
Typical Performance *click for larger image RF PLL Fin Sensitivity

Parameters / Values	LMX2485	LMX2485E	LMX2486	LMX2487	LMX2487E
Max PLL Freq	3000 MHz	3000 MHz	4500 MHz	6000 MHz	7500 MHz
Min PLL Freq	500 MHz	50 MHz	1000 MHz	1000 MHz	3000 MHz
Max Aux PLL Freq	800 MHz	800 MHz	3000 MHz	3000 MHz	3000 MHz
Min Aux PLL Freq	75 MHz	75 MHz	250 MHz	250 MHz	250 MHz
Normalized PLL Phase Noise	-210 dBc/Hz	-210 dBc/Hz	-210 dBc/Hz	-210 dBc/Hz	-210 dBc/Hz
Supply Current	5 mA	5 mA	8.5 mA	8.5 mA	8.5 mA
Number of PLLs	2	2	2	2	2
PLL Type	Delta-Sigma Fractional-N RF/IF Dual	Delta-Sigma Fractional-N RF/IF Dual	Delta-Sigma Fractional-N RF/IF Dual	Delta-Sigma Fractional-N RF/IF Dual	Delta-Sigma Fractional-N RF/IF Dual
Min Supply Voltage	2.5 Volt	2.5 Volt	2.5 Volt	2.5 Volt	2.5 Volt
Max Supply Voltage	3.6 Volt	3.6 Volt	3.6 Volt	3.6 Volt	3.6 Volt
Fastlock	Yes	Yes	Yes	Yes	Yes
Temperature Min	-40 deg C	-40 deg C	-40 deg C	-40 deg C	-40 deg C
Temperature Max	85 deg C	85 deg C	85 deg C	85 deg C	85 deg C
Power Consumption	Undefined Watt	Undefined Watt	Undefined Watt	Undefined Watt	Undefined Watt
PowerWise Rating 6	Undefined mW x ps /ch	Undefined mW x ps /ch	Undefined mW x ps /ch	Undefined mW x ps /ch	Undefined mW x ps /ch
PowerWise	Undefined	Undefined	Undefined	Undefined	Undefined

Datasheets

Title		Size	Date	Other Language
	LMX2485 Delta-Sigma Low Power Dual PLL for RF Personal Communications	763 Kbytes	27-Feb-08	日本語

Application Notes

Title		Size	Date	Other Language
	AN-1865: Application Note 1865 Frequency Synthesis and Planning for PLL Architectures	151 Kbytes	6-Feb-09
	AN-1879: Application Note 1879 Fractional N Frequency Synthesis	511 Kbytes	10-Dec-08

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LMX2485SQ/NOPB RoHS Status	LLP	Full production Lead Time: 6 weeks	Distributor Region Qty AVNET-EM Worldwide 1000 DIGI-KEY Worldwide 2235 MOUSER Worldwide 1000	$2.35 each at 1K+ pcs	reel of 1000
LMX2485SQX/NOPB RoHS Status	LLP	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$2.35 each at 1K+ pcs	reel of 4500

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LMX2485.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LMX2485 is located at RoHS Status.

Part Number(s) (NSID)	Description	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LMX24856211EVAL	Delta Sigma Low Power Dual PLL with External Active Filter	Full production	Distributor Region Qty MOUSER Worldwide 1	$176.00 each	1
LMX2485 evaluation board with LM6211 Active Filter. Contents: Evaluation Board Assembly PC Interface Cable Evaluation Board Operating Instructions PLL Selection Guide

Part Number(s) (NSID)	Description	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LMX2485EVAL	Delta-Sigma Low Power Dual PLL for RF Personal Communications	Full production	Distributor Region Qty	$176.00 each	1
Description: The LMX2485 Evaluation Board simplifies evaluation of the LMX2485 2.6 GHz/0.8 GHz PLLatinumTM dual frequency synthesizer. The board enables all performance measurements with no additional support circuitry. The evaluation board consists of a LMX2485 device, a RF VCO module and IF VCO & RF/IF loop filters built by discrete components. The SMA flange mount connectors are provided for external reference input, RF and IF VCO outputs, and the power and grounding connection. A cable assembly is bundled with the evaluation board for connecting to a PC through the parallel printer port. By means of MICROWIRETM serial port emulation, the Code-Loader software included can be run on a PC to facilitate the LMX2485 internal register programming for the evaluation and measurement. Contents: Evaluation Board Assembly PC Interface Cable Product Data Sheet LMX2485 Evaluation Board Instructions

National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C1) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/en/packaging/greennopb.html. Lead free products are RoHS compliant.

Lead Free product status is available through the search tool located here

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LMX2485SQ/NOPB	39.849	LLP	24	3	260	Detail	N/A	N/A	NS UZXYTT X2485DD
LMX2485SQX/NOPB	39.849	LLP	24	3	260	Detail	N/A	N/A	NS UZXYTT X2485DD

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LMX2485.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LMX2485 is located at RoHS Status.

Design Tools

Title	Size	Date
LMX2485 with Active Filter Using LM6211
LMX2485 Evaluation Board Instructions
Design and Simulation Software & CodeLoader Programming Software

CAD Symbols and Models N/A

Models N/A

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LMX2485SQ	BICMOS8	2	15238	132	0	1812500	2	514301823
LMX2485SQX	BICMOS8	2	15238	132	0	1812500	2	514301823

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LMX2485.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LMX2485 is located at RoHS Status.

Software-Defined Radio (SDR) Webinar Click image to play video in new window Clock & Timing - Low Noise Frequency Synthesizers Loading video...

Software-Defined Radio (SDR) Webinar Date: 2010-08-30 Length: 0:28:23 Clock & Timing - Low Noise Frequency Synthesizers Date: 2009-07-21 Length: 0:45:52