Features: Low in-band phase noise and low fractional spurs
12 bit or 22 bit selectable fractional modulus
Up to 4th order programmable delta-sigma modulator
Enhanced Anti-Cycle Slip Fastlock CircuitryFastlockCycle slip reductionIntegrated timeout counters
Digital lock detect output
Prescalers allow wide range of N valuesRF PLL: 16/17/20/21IF PLL: 8/9 or 16/17
Crystal Reference Frequency up to 110 MHz
On-chip crystal reference frequency doubler.
Phase Comparison Frequency up to 30 MHz
Hardware and software power-down control
Ultra low consumption: ICC = 4.1 mA (typical)Application Cellular Phones and Base StationsCDMA, WCDMA, GSM/GPRS, TDMA, EDGE, PDC
Applications requiring fine frequency resolution
WLAN StandardsPinout
Specifications
| Max PLL Freq |
2600 MHz |
| Max Aux PLL Freq |
800 MHz |
| Normalized PLL Phase Noise |
-210 dBc/Hz |
| Supply Min |
2.25 Volt |
| Supply Current |
4.1 mA |
| PLL Type |
Delta-Sigma Fractional-N |
| Fastlock |
Yes |
| Temperature Min |
-40 deg C |
| Temperature Max |
85 deg C |
| PowerWise |
Undefined |
| View Using Catalog |
|
Parameter |
Symbol |
Value |
Units |
|
Min |
Typ |
Max |
|
Power Supply Voltage |
VCC |
-0.3 |
|
3.0 |
V |
|
VDD |
VCC |
|
VCC |
V |
|
Voltage on any pin with GND =VSS =0V |
VI |
-0.3 |
|
VCC + 0.3 |
V |
|
Storage Temperature Range |
Ts |
-65 |
|
+150 |
|
|
Lead Temperature (Solder 4 sec.) |
TL |
|
|
+260 |
|
DescriptionThe LMX2470 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 BiCMOS process.
With delta-sigma architecture, fractional spur compensation is achieved with noise shaping capability of the delta-sigma modulator and the inherent low pass filtering of the PLL loop filter. Fractional spurs at lower frequencies are pushed to higher frequencies outside the loop bandwidth. Unlike analog compensation, the digital feedback techniques used in the LMX2470 are highly resistant to changes in temperature and variations in wafer processing. With delta-sigma architecture, the ability to push close in spur and phase noise energy to higher frequencies is a direct function of the modulator order. The higher the order, the more this energy can be spread to higher frequencies. The LMX2470 has a programmable modulator up to order four, which allows the designer to select the optimum modulator order to fit the phase noise, spur, and lock time requirements of the system.
Programming is fast and simple. Serial data is transferred into the LMX2470 via a three line MICROWIRE interface (Data, Clock, Load Enable). Nominal supply voltage is 2.5 V. The LMX2470 features a typical current consumption of 4.1 mA at 2.5 V. The LMX2470 is available in a 24 lead 3.5 X 4.5 X 0.6 mm package.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
| LMX2470SLEX |
BICMOS8 |
2 |
12313 |
163 |
0 |
1407500 |
3 |
399381968 |
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.
Design Tools
| Title |
Size in Kbytes |
Date |
|
|
|
| LMX2470 Evaluation Board Instructions |
912 Kbytes |
23-Feb-2004 |
View Online |
Download |
|
| LMX-Utility Evaluation Board: Add features and functionality to the standard evaluation boards, such as amplification, loop filter, and RF functions" |
|
|
View |
|
|
If you have trouble printing or viewing PDF file(s), see Printing Problems.
|
Application Notes
| Title |
Size in Kbytes |
Date |
|
| AN-1879: Application Note 1879 Fractional N Frequency Synthesis |
511 Kbytes |
10-Dec-08 |
Download |
If you have trouble printing or viewing PDF file(s), see Printing Problems.
|
LMX2470 Data Sheet
