參數(shù)資料
型號(hào): MAX9486EUG
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: XO, clock
英文描述: 8kHz Reference Clock Synthesizer with Multiple Outputs at 35.328MHz
中文描述: 35.328 MHz, OTHER CLOCK GENERATOR, PDSO24
封裝: 4.40 MM, MO-153AD, TSSOP-24
文件頁數(shù): 7/8頁
文件大?。?/td> 547K
代理商: MAX9486EUG
SHDN
Mode
The MAX9486 features a shutdown mode with a supply
current less than 8μA (typ). Drive
SHDN
low to get the
device into shutdown mode. In this mode, all the out-
puts go low and both PLLs are powered down. After
SHDN
goes high, the outputs still stay low for an addi-
tional 256ms to allow both PLLs to be stabilized before
the outputs are enabled again.
Applications Information
Crystal Selection
The MAX9486 uses a 17.664MHz crystal as the base
frequency for the VCXO. It is important to use a correct
type of quartz crystal to avoid reducing frequency
pulling range, or excessive output phase jitter.
Choose an AT-cut crystal that oscillates at 17.664MHz
on its fundamental mode with a variation of
±
25ppm
including frequency accuracy and operating tempera-
ture range. The crystal’s load capacitance should be
14pF. Pulling range may vary depending on the crystal
used. Refer to the MAX9486 evaluation kit for details.
PLL1 Loop Filter
The MAX9486 features two PLLs: PLL1 and PLL2. The
first phased-lock loop, PLL1, contains an integrated
VCXO that uses an external crystal to track the input
reference signal and attenuate input jitter. Figure 1
shows the external loop filter of the PLL containing
resistor R1 and two capacitors, C1 and C2. This loop
filter is connected between LP1 and LP2 as shown in
the
Typical Operating Circuit
. The loop-filter bandwidth
is determined by C1, C2, R1, and R
SET
where R
SET
is
used to set the value of the charge-pump current. The
typical values of C1, C2, R1, and R
SET
are 22nF,
560pF, 1000k
, and 13k
, respectively.
Use the following equation to calculate a PLL loop
bandwidth in Hz:
BW = (R1 x I
SETI
x 940) / N
where R1 (
) is the resistor in the PLL1 loop filter
(Figure 1), I
SETI
(A) is the charge-pump current calcu-
lated from the equation in the
Charge-Pump Current
Setting
section, and N is the crystal PLL frequency
divider equal to 2208.
The loop-damping factor is calculated by:
where C1 (F) and R1 (
) are the values of the capacitor
and the resistor in the PLL1 loop filter shown in
Figure 1; I
SETI
is calculated as shown in the
Charge-
Pump Current Setting
section and N = 2208.
The following equation shows the relationship between
components C1 and C2 in the loop filter:
C2
C1/20
Charge-Pump Current Setting
The MAX9486 also allows external setting of the charge-
pump current in PLL1. Connect a resistor from SETI to
GNDP to set the PLL1 charge-pump current:
Charge-Pump Current = 2.4 x 1000 / (R
SET
(k
) + 1)
where R
SET
is in k
and the value of the charge-pump
current is in μA.
The loop response can be adjusted to meet individual
application requirements since the charge-pump cur-
rent and all the filter components for the VCXO loop
can be set externally.
Board Layout and Bypassing
The MAX9486’s high-oscillator frequency makes proper
layout important to ensure stability. For best performance,
place components as close as possible to the device.
Digital or AC transient signals on GND can create noise
at the clock outputs. Return GND to the highest quality
ground available. Bypass V
DD
and V
DDP
with 0.1μF
and 0.001μF capacitors, placed as close to the device
as possible. Careful PC board ground layout minimizes
crosstalk between the outputs and digital inputs.
Traces must be as short as possible on LP1 and LP2
and connect the capacitors and the resistor as close as
possible to the device.
Chip Information
TRANSISTOR COUNT: 7512
PROCESS: CMOS
DampingFactor
R
2
I
N
C
SETI
=
×
×
×
1
1
5900
M
8kHz Reference Clock Synthesizer
with Multiple Outputs at 35.328MHz
_______________________________________________________________________________________
7
R1
C1
C2
LP1
LP2
Figure 1. Typical Loop Filter
相關(guān)PDF資料
PDF描述
MAX9486 8kHz Reference Clock Synthesizer with Multiple Outputs at 35.328MHz
MAX9503METE DirectDrive Video Amplifier with Reconstruction Filter
MAX9503GEEE DirectDrive Video Amplifier with Reconstruction Filter
MAX9503GETE DirectDrive Video Amplifier with Reconstruction Filter
MAX9503 DirectDrive Video Amplifier with Reconstruction Filter
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX9486EUG-T 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 35.328MHz Clock Synthesizer 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
MAX9486EVKIT 制造商:Maxim Integrated Products 功能描述:8KHZ REFERENCE CLOCK SYNTHESIZER WI - Bulk
MAX9489ETJ 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX9491ETP010 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 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
MAX9491ETP010+ 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 Factory-Prog Single PLL Clock Generator 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