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參數(shù)資料
| 型號： | AD9524BCPZ |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 15/56頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC INTEGER-N CLCK GEN 48LFCSP |
| 標(biāo)準(zhǔn)包裝： | 1 |
| 類型： | 時鐘/頻率發(fā)生器，扇出緩沖器（分配） |
| PLL： | 是 |
| 主要目的： | 以太網(wǎng)，光纖通道，SONET/SDH |
| 輸入： | CMOS |
| 輸出： | HSTL，LVCMOS，LVDS，LVPECL |
| 電路數(shù)： | 1 |
| 比率 - 輸入:輸出： | 2:6 |
| 差分 - 輸入:輸出： | 是/是 |
| 頻率 - 最大： | 1GHz |
| 電源電壓： | 1.71 V ~ 3.465 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 48-VFQFN 裸露焊盤，CSP |
| 供應(yīng)商設(shè)備封裝： | 48-LFCSP-VQ（7x7） |
| 包裝： | 托盤 |
| 相關(guān)產(chǎn)品： | AD9524BCPZ-REEL7DKR-ND - IC INTEGER-N CLCK GEN 48LFCSP AD9524BCPZ-REEL7CT-ND - IC INTEGER-N CLCK GEN 48LFCSP AD9524/PCBZ-ND - BOARD EVAL FOR AD9524 AD9524BCPZ-REEL7TR-ND - IC INTEGER-N CLCK GEN 48LFCSP |
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AD9524
Data Sheet
Rev. E | Page 22 of 56
Input 2× Frequency Multiplier
The 2× frequency multiplier provides the option to double
the frequency at the PLL2 input. This allows the user to take
advantage of a higher frequency at the input to the PLL (PFD)
and, thus, allows for reduced in-band phase noise and greater
separation between the frequency generated by the PLL and the
modulation spur associated with PFD. However, increased
reference spur separation results in harmonic spurs introduced
by the frequency multiplier that increase as the duty cycle deviates
from 50% at the OSC_IN inputs. As such, beneficial use of the
frequency multiplier is application-specific. Typically, a VCXO
with proper interfacing has a duty cycle that is approximately
50% at the OSC_IN inputs. Note that the maximum output
frequency of the 2× frequency multipliers must not exceed the
maximum PFD rate that is specified in Table 12.
PLL2 Feedback Divider
PLL2 has a feedback divider (N divider) that enables it to provide
integer frequency up-conversion. The PLL2 N divider is a com-
bination of a prescaler (P) and two counters, A and B. The total
divider value is
N = (P × B) + A
where P = 4.
The feedback divider is a dual modulus prescaler architecture,
with a nonprogrammable P that is equal to 4. The value of the B
counter can be from 4 to 63, and the value of the A counter can
be from 0 to 3. However, due to the architecture of the divider,
there are constraints, as listed in Table 46.
PLL2 Loop Filter
The PLL2 loop filter requires the connection of an external
capacitor from LF2_EXT_CAP (Pin 9) to LDO_VCO (Pin 12),
as illustrated in Figure 25. The value of the external capacitor
depends on the operating mode and the desired phase noise
performance. For example, a loop bandwidth of approximately
500 kHz produces the lowest integrated jitter. A lower bandwidth
produces lower phase noise at 1 MHz but increases the total
integrated jitter.
Table 21. PLL2 Loop Filter Programmable Values
RZERO
()
CPOLE1
(pF)
RPOLE2
()
CPOLE2
(pF)
LF2_EXT_CAP1
(pF)
3250
48
900
Fixed at 16
Typical at 1000
3000
40
450
2750
32
300
2500
24
225
2250
16
2100
8
2000
0
1850
1
External loop filter capacitor.
VCO Divider
The VCO divider provides frequency division between the internal
VCO and the clock distribution. The VCO divider can be set to
divide by 4, 5, 6, 7, 8, 9, 10, or 11.
VCO Calibration
The AD9524 on-chip VCO must be manually calibrated to ensure
proper operation over process and temperature. This is accom-
plished by setting the calibrate VCO bit (Register 0x0F3, Bit 1)
to 1. (This bit is not self-clearing.) The setting can be performed
as part of the initial setup before executing the IO_Update bit
(Register 0x234, Bit 0 = 1). A readback bit, VCO calibration
in progress (Register 0x22D, Bit 0), indicates when a VCO
calibration is in progress by returning a logic true (that is, Bit 0
= 1). If the EEPROM is in use, setting the calibrate VCO bit
(Register 0x0F3, Bit 1) to 1 before saving the register settings
to the EEPROM ensures that the VCO calibrates automatically
after the EEPROM has loaded. After calibration, it is recommended
that a sync be initiated (for more information, see the Clock
Distribution Synchronization section).
Note that the calibrate VCO bit defaults to 0. This bit must
change from 0 to 1 to initiate a calibration sequence. Therefore,
any subsequent calibrations require the following sequence:
1. Register 0x0F3, Bit 1 (calibrate VCO bit) = 0
2. Register 0x234, Bit 0 (IO_Update bit) = 1
3. Register 0x0F3, Bit 1 (calibrate VCO bit) = 1
4. Register 0x234, Bit 0 (IO_Update bit) = 1
VCO calibration is controlled by a calibration controller that runs
off the VCXO input clock. The calibration requires that PLL2 be
set up properly to lock the PLL2 loop and that the VCXO clock
be present.
During power-up or reset, the distribution section is automatically
held in sync until the first VCO calibration is finished. Therefore,
no outputs can occur until VCO calibration is complete and PLL2
is locked.
Initiate a VCO calibration under the following conditions:
After changing any of the PLL2 B counter and A counter
settings or after a change in the PLL2 reference clock
frequency. This means that a VCO calibration should be
initiated any time that a PLL2 register or reference clock
changes such that a different VCO frequency is the result.
Whenever system calibration is desired. The VCO is designed
to operate properly over extremes of temperature even when
it is first calibrated at the opposite extreme. However, a VCO
calibration can be initiated at any time, if desired.
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| AD9524BCPZ-REEL7 | 功能描述:IC INTEGER-N CLCK GEN 48LFCSP RoHS:是 類別:集成電路 (IC) >> 時鐘/計時 - 專用 系列:- 標(biāo)準(zhǔn)包裝:28 系列:- 類型:時鐘/頻率發(fā)生器 PLL:是 主要目的:Intel CPU 服務(wù)器 輸入:時鐘 輸出:LVCMOS 電路數(shù):1 比率 - 輸入:輸出:3:22 差分 - 輸入:輸出:無/是 頻率 - 最大:400MHz 電源電壓:3.135 V ~ 3.465 V 工作溫度:0°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:64-TFSOP （0.240"，6.10mm 寬） 供應(yīng)商設(shè)備封裝:64-TSSOP 包裝:管件 |
| AD9525 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Low Jitter Clock Generator with Eight LVPECL Outputs |
| AD9525/PCBZ | 功能描述:時鐘和定時器開發(fā)工具 Evaluation kit 2950MHz VCO installed RoHS:否 制造商:Texas Instruments 產(chǎn)品:Evaluation Modules 類型:Clock Conditioners 工具用于評估:LMK04100B 頻率:122.8 MHz 工作電源電壓:3.3 V |
| AD9525/PCBZ-VCO | 功能描述:時鐘和定時器開發(fā)工具 Evaluation kit CRO29508 VCO installed RoHS:否 制造商:Texas Instruments 產(chǎn)品:Evaluation Modules 類型:Clock Conditioners 工具用于評估:LMK04100B 頻率:122.8 MHz 工作電源電壓:3.3 V |
| AD9525BCPZ | 功能描述:時鐘發(fā)生器及支持產(chǎn)品 High performance clock distributor Exter RoHS:否 制造商:Silicon Labs 類型:Clock Generators 最大輸入頻率:14.318 MHz 最大輸出頻率:166 MHz 輸出端數(shù)量:16 占空比 - 最大:55 % 工作電源電壓:3.3 V 工作電源電流:1 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-56 |
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