- 您現在的位置：買賣IC網 > PDF目錄363887 > W48C101 (Cypress Semiconductor Corp.) Spread Spectrum BX System Frequency Generator PDF資料下載
參數資料
| 型號： | W48C101 |
| 廠商： | Cypress Semiconductor Corp. |
| 英文描述： | Spread Spectrum BX System Frequency Generator |
| 中文描述： | 擴頻顏Bx系統頻率發生器 |
| 文件頁數： | 3/8頁 |
| 文件大小： | 112K |
| 代理商： | W48C101 |
W48C101-01
PRELIMINARY
3
Spread Spectrum Clocking
The device generates a clock that is frequency modulated in
order to increase the bandwidth that it occupies. By increasing
the bandwidth of the fundamental and its harmonics, the am-
plitudes of the radiated electromagnetic emissions are re-
duced. This effect is depicted in
Figure 1
.
As shown in
Figure 1
, a harmonic of a modulated clock has a
much lower amplitude than that of an unmodulated signal. The
reduction in amplitude is dependent on the harmonic number
and the frequency deviation or spread. The equation for the
reduction is:
dB = 6.5 + 9*log
10
(P) + 9*log
10
(F)
Where
P
is the percentage of deviation and
F
is the frequency
in MHz where the reduction is measured.
The output clock is modulated with a waveform depicted in
Figure 2
. This waveform, as discussed in
“
Spread Spectrum
Clock Generation for the Reduction of Radiated Emissions
”
by
Bush, Fessler, and Hardin produces the maximum reduction
in the amplitude of radiated electromagnetic emissions. The
deviation selected for this chip is
–
0.5%,
–
1.0%, or ±0.9% of
the selected frequency.
Figure 2
details the Cypress spreading
pattern. Cypress does offer options with more spread and
greater EMI reduction. Contact your local Sales representative
for details on these devices.
Spread Spectrum clocking is activated or deactivated by se-
lecting the appropriate values for SPREAD#.
Figure 1. Clock Harmonic with and without SSCG Modulation Frequency Domain Representation
SSC
non-SSC
Highest peak
δ
of f
nom
f
nom
MAX (+0.5%)
MIN (
–
0.5%)
1
2
3
4
5
6
7
8
9
1
1
2
3
4
5
6
7
8
9
1
F
Figure 2. Typical Modulation Profile
相關PDF資料 |
PDF描述 |
|---|---|
| W48C111-16 | Frequency Generator for Integrated Core Logic(在集成核心邏輯中應用的頻率發生器) |
| W48C111-17 | 100-MHz Mobile Motherboard System Clock(100-MHz 移動主板系統時鐘) |
| W48C111 | Frequency Generator for Integrated Core Logic |
| W48C20 | Audio Subsystem Clock Generator(音頻子系統時鐘發生器) |
| W48C55A | Frequency Synthesizers(頻率合成器) |
相關代理商/技術參數 |
參數描述 |
|---|---|
| W48C101-01 | 制造商:SPECTRALINEAR 制造商全稱:SPECTRALINEAR 功能描述:Spread Spectrum BX System Frequency Generator |
| W48C101-01H | 制造商:Cypress Semiconductor 功能描述: 制造商:IC WORKS 功能描述: |
| W48C101-01HT | 制造商:Cypress Semiconductor 功能描述: 制造商:IC Works Inc 功能描述:100 MHz, PROC SPECIFIC CLOCK GENERATOR, 48 Pin Plastic SMT |
| W48C101-01HTR | 制造商:IC_WORKS 功能描述: |
| W48C111 | 制造商:CYPRESS 制造商全稱:Cypress Semiconductor 功能描述:Frequency Generator for Integrated Core Logic |
發布緊急采購，3分鐘左右您將得到回復。