参数资料
| 型号： | ADF4351BCPZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 17/28页 |
| 文件大小： | 0K |
| 描述： | IC SYNTH PLL VCO 32LFCSP |
| 标准包装： | 1 |
| 类型： | 扇出配送，分数-N，整数-N，时钟/频率合成器（RF） |
| PLL： | 是 |
| 输入： | CMOS，TTL |
| 输出： | 时钟 |
| 电路数： | 1 |
| 比率 - 输入:输出： | 1:3 |
| 差分 - 输入:输出： | 无/无 |
| 频率 - 最大： | 4.4GHz |
| 除法器/乘法器： | 是/是 |
| 电源电压： | 3 V ~ 3.6 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘，CSP |
| 供应商设备封装： | 32-LFCSP（5x5） |
| 包装： | 托盘 |
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ADF4351
Data Sheet
Rev. 0 | Page 24 of 28
SPUR CONSISTENCY AND FRACTIONAL SPUR
OPTIMIZATION
With dither off, the fractional spur pattern due to the quantiza-
tion noise of the Σ-Δ modulator also depends on the particular
phase word with which the modulator is seeded.
The phase word can be varied to optimize the fractional and
subfractional spur levels on any particular frequency. Thus, a
lookup table of phase values corresponding to each frequency
can be created for use when programming the ADF4351.
If a lookup table is not used, keep the phase word at a constant
value to ensure consistent spur levels on any particular frequency.
PHASE RESYNC
The output of a fractional-N PLL can settle to any one of the
MOD phase offsets with respect to the input reference, where
MOD is the fractional modulus. The phase resync feature of
the ADF4351 produces a consistent output phase offset with
respect to the input reference. This phase offset is necessary in
applications where the output phase and frequency are important,
such as digital beamforming. See the Phase Programmability
section to program a specific RF output phase when using
phase resync.
Phase resync is enabled by setting Bits[DB16:DB15] in
Register 3 to 10. When phase resync is enabled, an internal
timer generates sync signals at intervals of tSYNC given by the
following formula:
tSYNC = CLK_DIV_VALUE × MOD × tPFD
where:
CLK_DIV_VALUE is the decimal value programmed in
Bits[DB14:DB3] of Register 3. This value can be any integer
from 1 to 4095.
MOD is the modulus value programmed in Bits[DB14:DB3]
of Register 1 (R1).
tPFD is the PFD reference period.
When a new frequency is programmed, the second sync pulse
after the LE rising edge is used to resynchronize the output
phase to the reference. The tSYNC time must be programmed to
a value that is at least as long as the worst-case lock time. This
guarantees that the phase resync occurs after the last cycle slip
in the PLL settling transient.
In the example shown in Figure 33, the PFD reference is 25 MHz
and MOD = 125 for a 200 kHz channel spacing. tSYNC is set to
400 s by programming CLK_DIV_VALUE = 80.
LE
PHASE
FREQUENCY
SYNC
(INTERNAL)
–100
0
100
200
1000
300
400
500
600
700
800
900
TIME (s)
PLL SETTLES TO
CORRECT PHASE
AFTER RESYNC
tSYNC
LAST CYCLE SLIP
PLL SETTLES TO
INCORRECT PHASE
09800-
020
Figure 33. Phase Resync Example
Phase Programmability
The phase word in Register 1 controls the RF output phase. As
this word is swept from 0 to MOD, the RF output phase sweeps
over a 360° range in steps of 360°/MOD. In many applications,
it is advisable to disable VCO band selection by setting Bit DB28
in Register 1 (R1) to 1. This setting selects the phase adjust feature.
High PFD Frequencies
VCO band selection is required to ensure that the correct VCO
band is chosen for the relevant frequency. VCO band selection
can operate with PFD frequencies up to 45 MHz using the high
VCO band select mode (set Bit DB23 in Register 3 to 1).
For PFD frequencies higher than 45 MHz, it is recommended
that the user perform the following steps:
1. Program the desired VCO frequency with phase adjustment
disabled (set Bit DB28 in Register 1 to 0). Ensure that the
PFD frequency is less than 45 MHz.
2. After the correct frequency is achieved, enable phase adjust-
ment (set Bit DB28 in Register 1 to 1).
3. PFD frequencies higher than 32 MHz are permissible only
with integer-N applications; therefore, set the antibacklash
pulse width to 3 ns (set Bit DB22 in Register 3 to 1).
4. Using the desired PFD frequency, program the appropriate
values for the reference R and feedback N counters.
Using this procedure, the lowest rms in-band phase noise can
be achieved.
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相关代理商/技术参数 |
参数描述 |
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| ADF4351BCPZ-RL7 | 功能描述:IC SYNTH PLL VCO 32LFCSP RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:- 标准包装:2,000 系列:- 类型:PLL 时钟发生器 PLL:带旁路 输入:LVCMOS，LVPECL 输出:LVCMOS 电路数:1 比率 - 输入:输出:2:11 差分 - 输入:输出:是/无 频率 - 最大:240MHz 除法器/乘法器:是/无 电源电压:3.135 V ~ 3.465 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:32-LQFP 供应商设备封装:32-TQFP（7x7） 包装:带卷 (TR) |
| ADF4351BCPZ-U5 | 制造商:Analog Devices 功能描述:- Rail/Tube |
| ADF4351BCPZ-U6 | 制造商:Analog Devices 功能描述:WIDEBAND SYNTHESIZER WITH INTEGRATED VCO - Rail/Tube |
| ADF4355-2BCPZ | 功能描述:IC INTEGRATED SYNTH/VCO 32LFCSP 制造商:analog devices inc. 系列:- 包装:托盘 零件状态:有效 类型:* PLL:是 输入:时钟 输出:时钟 电路数:1 比率 - 输入:输出:1:2 差分 - 输入:输出:无/无 频率 - 最大值:4.4GHz 分频器/倍频器:是/是 电压 - 电源:3.15 V ~ 3.45 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:32-WFQFN 裸露焊盘，CSP 供应商器件封装:32-LFCSP-WQ（5x5） 标准包装:1 |
| ADF4355-2BCPZ-RL7 | 功能描述:IC INTEGRATED SYNTH/VCO 32LFCSP 制造商:analog devices inc. 系列:- 包装:带卷（TR） 零件状态:有效 类型:* PLL:是 输入:时钟 输出:时钟 电路数:1 比率 - 输入:输出:1:2 差分 - 输入:输出:无/无 频率 - 最大值:4.4GHz 分频器/倍频器:是/是 电压 - 电源:3.15 V ~ 3.45 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:32-WFQFN 裸露焊盘，CSP 供应商器件封装:24-LFCSP-WQ（4x4） 标准包装:1,500 |
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