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參數(shù)資料
| 型號(hào)： | LC72148V |
| 廠商： | Sanyo Electric Co.,Ltd. |
| 英文描述： | Electronic Tuning PLL Frequency Synthesizer for Car Stereo Systems |
| 中文描述： | 電子調(diào)諧鎖相環(huán)頻率合成器的汽車音響系統(tǒng) |
| 文件頁數(shù)： | 18/21頁 |
| 文件大小： | 170K |
| 代理商： | LC72148V |
Other Items
1. Notes on the phase comparator dead band
When the charge pumps are in one of the ON/ON states, correction pulses will be output from the charge pumps even
if the PLL is locked, making it easier for the loop to become unstable. Thus particular care is required in the design
stage for these settings.
The following problems may occur when the ON/ON states are used.
(1) Side bands may be created by reference frequency leakage.
(2) Side bands may be created by low-frequency leakage due to the envelope of the correction pulses.
When a dead band is present (the OFF/OFF settings), the loop will be stable. However, it will be difficult to achieve a
high signal-to-noise ratio. Inversely, with no dead band, it is easy to achieve a high signal-to-noise ratio but hard to
achieve high loop stability.
Therefore, the DZA and DZB settings, in which there is no dead band, can be effective for cases where an FM signal-
to-noise ratio of 90 to 100 dB or greater is required, or when it is desirable to increase the AM stereo pilot margin.
However, if such a high signal-to-noise ratio is not required in FM reception, or an adequate AM stereo pilot margin
can be achieved, or AM stereo is not used, DZC or DZD, which provide a dead band, should be selected.
Dead Zone (Dead Band) Definition
The phase comparator compares fp with the reference frequency (fr) as shown in figure 1. This circuit outputs a level
(A) that is proportional to the phase difference as shown in figure 2. However, due to internal delays and other
factors, the actual IC is unable to compare small phase differences, and thus a dead zone (B) appears in the output. To
achieve a high signal-to-noise ratio in the end product, the dead zone should be as small as possible.
However, in popularly-priced models, there are cases where a somewhat wider dead zone may be easier to work with.
This is because in some situations, such as when a powerful signal is applied to the RF input, in popularly-priced
models there may be RF leakage from the mixer to the VCO. When the dead zone is narrow, outputs to correct this
leakage are output, that output in turn modulates the VCO, and generates a beat signal with the RF.
2. Notes on the FMIN, AMIN, HCTR/I-6, and LCTR/I-7 pins
The coupling capacitors must be located as close as possible to these pins. A capacitance of approximately 100 pF is
desirable.
In particular, if the HCTR/I-6 and LCTR/I-7 pin capacitors are over about 1000 pF, the time required to reach the bias
level may become excessive, and incorrect counting may occur due to the relationship with the wait time.
No. 6974-18/21
LC72148V
DZ1
DZ0
Dead band mode
Charge pumps
Dead band
0
0
DZA
ON/ON
- - 0 s
0
1
DZB
ON/ON
- 0 s
1
0
DZC
OFF/OFF
+0 s
1
1
DZD
OFF/OFF
++0 s
Reference divider
Programmable divider
fr
fp
Phase
Detector
RF
MIX
LPF
VCO
Leakage
V
(A)
(B)
(ns)
Dead Zone
Figure 1
Figure 2
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LC72148V-MPB-E | 制造商:ON Semiconductor 功能描述:PLL FREQUENCY SYNTHESIZER - Ammo Pack 制造商:ON Semiconductor 功能描述:Phase Locked Loops - PLL |
| LC72148V-TLM-E | 功能描述:時(shí)鐘合成器/抖動(dòng)清除器 RoHS:否 制造商:Skyworks Solutions, Inc. 輸出端數(shù)量: 輸出電平: 最大輸出頻率: 輸入電平: 最大輸入頻率:6.1 GHz 電源電壓-最大:3.3 V 電源電壓-最小:2.7 V 封裝 / 箱體:TSSOP-28 封裝:Reel |
| LC7215 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:MW/LW PLL Frequency Synthesizers |
| LC72151V | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:PLL Frequency Synthesizer for Electronic Tuning in Car Audio Systems |
| LC72151VS-MPB-E | 制造商:ON Semiconductor 功能描述:PLL FREQUENCY SYNTHESIZER - Ammo Pack |
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