參數(shù)資料
型號(hào)： ADF4154
廠商： Analog Devices, Inc.
元件分類： XO, clock
英文描述： Fractional-N Frequency Synthesizer
中文描述： 分?jǐn)?shù)N頻率合成器
文件頁(yè)數(shù)： 9/20頁(yè)
文件大?。?/td> 470K
代理商： ADF4154
ADF4154
CIRCUIT DESCRIPTION
REFERENCE INPUT SECTION
The reference input stage is shown in Figure 17. SW1 and SW2
are normally closed switches. SW3 is normally open. When
power-down is initiated, SW3 is closed and SW1 and SW2 are
opened. This ensures that the REF
IN
pin is not loaded on
power-down.
Rev. 0 | Page 9 of 20
BUFFER
TO R COUNTER
REF
IN
100k
NC
SW2
SW3
NO
NC
SW1
POWER-DOWN
CONTROL
0
Figure 17. Reference Input Stage
RF INPUT STAGE
The RF input stage is shown in Figure 18. It is followed by a
2-stage limiting amplifier to generate the current mode logic
(CML) clock levels needed for the prescaler.
BIAS
GENERATOR
1.6V
AGND
AV
DD
2k
2k
RF
IN
B
RF
IN
A
0
Figure 18. RF Input Stage
RF INT DIVIDER
The RF INT CMOS counter allows a division ratio in the PLL
feedback counter. Division ratios from 31 to 511 are allowed.
INT, FRAC, MOD, AND R RELATIONSHIP
The INT, FRAC, and MOD values, in conjunction with the
R counter, make it possible to generate output frequencies that
are spaced by fractions of the phase frequency detector (PFD).
See the RF Synthesizer: A Worked Example section for more
information. The RF VCO frequency (
RF
OUT
) equation is
(
FRAC
INT
F
RF
PFD
OUT
)
(
)
MOD
+
×
=
(1)
where
RF
OUT
is the output frequency of the external voltage
controlled oscillator (VCO).
(
)
R
D
REF
F
IN
PFD
+
×
=
1
(2)
where:
REF
IN
is the reference input frequency.
D
is the
REF
IN
doubler bit.
R
is the preset divide ratio of binary 4-bit programmable
reference counter (1 to 15).
INT
is the preset divide ratio of binary 9-bit counter (31 to 511).
MOD
is the preset modulus ratio of binary 12-bit program-
mable FRAC counter (2 to 4095).
FRAC
is the preset fractional ratio of binary 12-bit
programmable FRAC counter (0 to MOD).
RF R COUNTER
The 4-bit RF R counter allows the input reference frequency
(REF
IN
) to be divided down to produce the reference clock to
the PFD. Division ratios from 1 to 15 are allowed.
THIRD ORDER
FRACTIONAL
INTERPOLATOR
FRAC
VALUE
MOD
REG
INT
REG
RF N-DIVIDER
N = INT + FRAC/MOD
FROM RF
INPUT STAGE
TO PFD
N COUNTER
0
Figure 19. A and B Counters
PHASE FREQUENCY DETECTOR (PFD) AND
CHARGE PUMP
The PFD takes inputs from the R counter and N counter and
produces an output proportional to the phase and frequency
difference between them. Figure 20 is a simplified schematic.
The PFD includes a fixed delay element that sets the width of
the antibacklash pulse, which is typically 3 ns. This pulse
ensures that there is no dead zone in the PFD transfer function
and gives a consistent reference spur level.
UP
HI
Q1
D1
U3
CLR2
D2
U2
Q2
DOWN
HI
CP
–IN
+IN
CHARGE
PUMP
DELAY
CLR1
U1
0
Figure 20. PFD Simplified Schematic
相關(guān)PDF資料
PDF描述
ADF4154BCP Fractional-N Frequency Synthesizer
ADF4154BCP-REEL Fractional-N Frequency Synthesizer
ADF4154BCP-REEL7 Fractional-N Frequency Synthesizer
ADF4154BRU Fractional-N Frequency Synthesizer
ADF4154BRU-REEL Fractional-N Frequency Synthesizer
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADF4154BCP 制造商:Analog Devices 功能描述:PLL Frequency Synthesizer Single 20-Pin LFCSP EP 制造商:Rochester Electronics LLC 功能描述:FRACTIONAL-N SYNTH. W/FASTLOCK COUNTER - Bulk
ADF4154BCP-REEL 制造商:Analog Devices 功能描述:PLL Frequency Synthesizer Single 20-Pin LFCSP EP T/R 制造商:Rochester Electronics LLC 功能描述:FRACTIONAL-N SYNTH. W/FASTLOCK COUNTER - Tape and Reel
ADF4154BCP-REEL7 制造商:Analog Devices 功能描述:PLL Frequency Synthesizer Single 20-Pin LFCSP EP T/R
ADF4154BCPZ 功能描述:IC FRACTION-N FREQ SYNTH 20LFCSP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器，PLL，頻率合成器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:Precision Edge® 類型:時(shí)鐘/頻率合成器 PLL:無 輸入:CML，PECL 輸出:CML 電路數(shù):1 比率 - 輸入:輸出:2:1 差分 - 輸入:輸出:是/是 頻率 - 最大:10.7GHz 除法器/乘法器:無/無 電源電壓:2.375 V ~ 3.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-VFQFN 裸露焊盤，16-MLF? 供應(yīng)商設(shè)備封裝:16-MLF?（3x3） 包裝:帶卷 (TR) 其它名稱:SY58052UMGTRSY58052UMGTR-ND
ADF4154BCPZ-RL 功能描述:IC FRACTION-N FREQ SYNTH 20LFCSP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器，PLL，頻率合成器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:Precision Edge® 類型:時(shí)鐘/頻率合成器 PLL:無 輸入:CML，PECL 輸出:CML 電路數(shù):1 比率 - 輸入:輸出:2:1 差分 - 輸入:輸出:是/是 頻率 - 最大:10.7GHz 除法器/乘法器:無/無 電源電壓:2.375 V ~ 3.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-VFQFN 裸露焊盤，16-MLF? 供應(yīng)商設(shè)備封裝:16-MLF?（3x3） 包裝:帶卷 (TR) 其它名稱:SY58052UMGTRSY58052UMGTR-ND
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