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參數(shù)資料
| 型號： | S1M8831A |
| 廠商： | SAMSUNG SEMICONDUCTOR CO. LTD. |
| 英文描述： | FRACTIONAL-N RF/INTEGER-N IF DUAL PLL |
| 中文描述： | 分數(shù)N射頻/整數(shù)N如果雙鎖相環(huán) |
| 文件頁數(shù)： | 14/32頁 |
| 文件大小： | 248K |
| 代理商： | S1M8831A |
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S1M8831A/33
FRACTIONAL-N RF/INTEGER-N IF DUAL PLL
14
∑
-
Modulator
The RF part of S1M8831A/33 adopts the
Σ
-
modulator as a core of the fractional counter that makes it possible
to obtain divide ratio N to be a fractional number between two contiguous integers. The
Σ
-
modulator effectively
randomizes the quantization noise generated from digitizing process and results in extreme suppression of in-
band noise power by pushing it out to out-of-band as in conventional
Σ
-
data converter. This technique
eliminates the need for compensation current injection into the loop filter and improves fractional spurious
performance, suitable for high-tier applications.
The
∑
-
modulator operates only for fractional-N mode, when the Frac-N_SEL is HIGH.
For proper use of the fractional mode, the user should be kept in mind that
1.
A fractional number should be set in the range from -0.5 to 0.5 in step of 1/62976.
The clock frequency fixed at 9.84MHz ( = 19.68MHz/2) is recommended for the
∑
-
modulator which is an
optimum condition for achieving better electrical performances related to the fractional noise and power
consumption. Only when using the clock frequency, the S1M8831A/33 guarantees the exact frequency
resolutions: 10kHz for CDMA PCS and 30kHz for CDMA cellular.
Note that the clock frequency much lower than 9.84MHz can deteriorate the fractional noise performance.
2.
Phase-Frequency Detector (PFD) and Charge Pump (CP)
The RF/IF phase detector composed of PFD and CP outputs pump current into an external loop filter in
proportional to the phase difference between outputs of N and R counter . The phase detector has a better linear
transfer characteristic due to a feedback loop to eliminate dead zone. The polarity of the PFD can be
programmed using RF_PFD_POL/IF_PFD_POL depending on whether RF/IF VCO characteristics are positive or
negative. (programming descriptions for phase detector polarity)
Power-Down (or Power-Save) Control
Each PLL is individually power controlled by the enable pins (RF_EN and IF_EN pins) or program control bits
(PWDN, PWDN_RF/IF). The enable pins override the program control bits. When both enable pins are HIGH, the
program control bits determine the state of power control. Power down forces all the internal blocks to be
deactivated and the charge pump output to be in the TRISTATE. The control register, however, remains active
for serial programming and is capable of loading and latching in data during the power down.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| S1M8831A/33 | 制造商:SAMSUNG 制造商全稱:Samsung semiconductor 功能描述:FRACTIONAL-N RF/INTEGER-N IF DUAL PLL |
| S1M8831A01-G0T0 | 制造商:SAMSUNG 制造商全稱:Samsung semiconductor 功能描述:FRACTIONAL-N RF/INTEGER-N IF DUAL PLL |
| S1M8833 | 制造商:SAMSUNG 制造商全稱:Samsung semiconductor 功能描述:FRACTIONAL-N RF/INTEGER-N IF DUAL PLL |
| S1M8833X01-G0T0 | 制造商:SAMSUNG 制造商全稱:Samsung semiconductor 功能描述:FRACTIONAL-N RF/INTEGER-N IF DUAL PLL |
| S1M8836 | 制造商:SAMSUNG 制造商全稱:Samsung semiconductor 功能描述:FRACTIONAL-N RF/INTEGER-N IF DUAL PLL |
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