參數(shù)資料
型號： LMX9830
廠商： National Semiconductor Corporation
英文描述： BluetoothTM Serial Port Module
中文描述： 藍(lán)牙串口模塊
文件頁數(shù)： 22/46頁
文件大?。?/td> 664K
代理商： LMX9830
www.national.com
22
L
9.0 Digital Smart Radio
(Continued)
Based on crystal spec and equation:
C
L
= C
int
+ C
TUNE
+ Ct1//Ct2
C
L
= 8pF + 2.6pF + 6pF = 16.6pF
16.6pF is very close to the TEW crystal requirement of
16pF load capacitance. With the internal shunt capacitance
C
total
:
C
total
= 16.6pF + 5pF = 21.6pF
Figure 12. LMX9830 Crystal Recommended
Circuit
Figure 13. Crystal Equivalent Circuit
2. Crystal Pullability
Pullability is another important parameter for a crystal,
which is the change in frequency of a crystal with units of
ppm/pF, either from the natural resonant frequency to a
load resonant frequency, or from one load resonant fre-
quency to another. The frequency can be pulled in a paral-
lel resonant circuit by changing the value of load
capacitance. A decrease in load capacitance causes an
increase in frequency, and an increase in load capacitance
causes a decrease in frequency.
3. Frequency Tuning
Frequency Tuning is achieved by adjusting the crystal load
capacitance with external capacitors. It is a Bluetooth
requirement that the frequency is always within
±
20 ppm.
Crystal/oscillator must have cumulative accuracy specifica-
tions of
+15 ppm
to provide margin for frequency drift with
aging and temperature.
TEW Crystal
The LMX9830 has been tested with the TEW TAS-4025A
crystal, reference Table 19 on page 22 for specification.
Since the internal capacitance of the crystal circuit is 8 pF
and the load capacitance is 16 pF, 12 pF is a good starting
point for both Ct1 and Ct2. The 2480 MHz RF frequency
offset is then tested. Figure 14 on page 23 shows the RF
frequency offset test results.
Figure 14 on page 23 shows the results are -20 kHz off the
center frequency, which is –1 ppm. The pullability of the
crystal is 2 ppm/pF, so the load capacitance must be
decreased by about 1.0 pF. By changing Ct1 or Ct2 to 10
pF, the total load capacitance is decreased by 1.0 pF. Fig-
ure 15 on page 23 shows the frequency offset test results.
The frequency offset is now zero with Ct1 = 10 pF, Ct2 = 10
pF.
Reference Table 20 on page 22 for crystal tuning values
used on Mesa Development Board with TEW crystal.
CLK+
CLK-
Ct1
Ct2
Crystal
LMX9830
C
int
C
TUNE
R1
C1
L1
C0
Table 19. TEW TAS-4025A
Specification
Value
Package
4.0x2.5x0.65 mm - 4 pads
Frequency
13.000 MHz
Mode
Fundamental
Stability
> ±15ppm @-40 to +85C
C
L
Load Capacitance
16pF
ESR
80
max.
C
0
Shunt Capacitance
5pF
Drive Level
50 ±10uV
Pullability
2 ppm/pF min
Storage Temperature
-40 to +85C
Table 20. TEW on LMX9830 DONGLE
Reference
LMX9830
Ct1
12pF
Ct2
12pF
相關(guān)PDF資料
PDF描述
LMX9830SM BluetoothTM Serial Port Module
LMX9830SMX BluetoothTM Serial Port Module
LMX9838 Bluetooth Serial Port Module
LMX9838SB Bluetooth Serial Port Module
LMX9838SBX Bluetooth Serial Port Module
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LMX9830DONGLE 功能描述:藍(lán)牙/802.15.1 開發(fā)工具 LMX9830 BLUETOOTH EVAL KIT RoHS:否 制造商:Panasonic Electronic Components 產(chǎn)品:Bluetooth Evaluation Kit 工具用于評估:PAN1721 頻率:2.4 GHz 接口類型:I2C 工作電源電壓:2 V to 3.6 V
LMX9830DONGLE/NOPB 制造商:Texas Instruments 功能描述:Evaluation Kit For Bluetooth Serial Port Module
LMX9830SM 制造商:NSC 制造商全稱:National Semiconductor 功能描述:BluetoothTM Serial Port Module
LMX9830SM/NOPB 功能描述:射頻收發(fā)器 RoHS:否 制造商:Atmel 頻率范圍:2322 MHz to 2527 MHz 最大數(shù)據(jù)速率:2000 Kbps 調(diào)制格式:OQPSK 輸出功率:4 dBm 類型: 工作電源電壓:1.8 V to 3.6 V 最大工作溫度:+ 85 C 接口類型:SPI 封裝 / 箱體:QFN-32 封裝:Tray
LMX9830SMX 制造商:NSC 制造商全稱:National Semiconductor 功能描述:BluetoothTM Serial Port Module
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