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參數(shù)資料
| 型號： | ML6553 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Bus Termination Regulator |
| 中文描述： | 總線終端穩(wěn)壓器 |
| 文件頁數(shù)： | 5/7頁 |
| 文件大?。?/td> | 115K |
| 代理商： | ML6553 |
PRODUCT SPECIFICATION
ML6553
REV. 1.0.2 3/21/01
5
Design Consideration
Inductor Selection
The ML6553 requires the selection of an external inductor.
A value of 4.7μH is a good choice, but any value between
2.2μH and 10μH is acceptable. Choosing an inductance
value of less than 2.2μH will reduce the component’s foot-
print or the DC resistance, but the output voltage ripple will
increase. Conversely, inductance values greater than 10μH
will reduce the output ripple, but component size and output
regulation become issues.
It is important to use an inductor that is rated to handle 1.5A
peak currents without saturating. Also look for an inductor
with low winding resistance. An inductor with low winding
resistance leads to better regulation and higher output current
capability. A good rule of thumb is to use inductors with
20m
or less of winding resistance.
The final selection of the inductor will be based on trade-offs
between size, cost and performance. Make your selections
carefully. Inductor tolerance, core and copper loss will vary
with the type of inductor selected and should be evaluated
with the ML6553 under worst case conditions to determine
its suitability.
Suggested inductor for L1:
Coiltronics
(561) 241-7876
Output Capacitor
The output capacitor filters the pulses of current from the bus
terminator regulator as well as lowers the AC output imped-
ance. For the best performance, one 330μF OS-CON decou-
pling capacitor is recommended.
Note that data transitions on the bus cause fast changes in
output current. These fast current changes cause high
frequency spikes to appear on the output. To minimize these
effects, choose an output capacitor with a combined ESR of
less than 50m
and use good layout practices to minimize
trace inductance from the output capacitors to the termina-
tion resistors. In addition, it is also recommended to bypass
the termination resistors with 0.01μF ceramic capacitors.
Suitable capacitors can be obtained from the following
vendors:
AVX
Sanyo
(207) 282-5111
(619) 661-6835
TPS Series
OS-CON Series
Input Capacitor
It is recommended to de-couple the PV
to 100μF capacitor. This provides the benefits of preventing
the input ripple from affecting the ML6553 control circuitry,
as well as improves the efficiency by reducing the I squared
R losses during the charge cycle of the inductor. Again, a low
ESR capacitor (such as tantalum) is recommended.
DD
input with a 47μF
The AV
ceramic capacitor but a low pass RC filter is recommended if
the supply is particularly noisy. If a RC filter is used, the
series resistor value needs to low enough to prevent exces-
sive voltage drops and high enough to provide effective
filtering. Resistor values on the order of 100
able.
CC
input should be de-coupled with at least a
are accept-
The V
if noise is present. The V
low pass RC filter if there is significant noise pickup on its
input. If a RC filter is used, resistor values on the order of
1,000
are acceptable.
CCQ
pin can also be bypassed with a ceramic capacitor
CCQ
pin can be de-coupled with a
Layout
Good layout practices will ensure the proper operation of the
ML6553. Some layout guidelines follow:
Use adequate ground and power traces or planes.
Keep the 47μF-100μF input capacitor as close to PV
and DGND as possible.
Use short trace lengths from the inductor to the V
and from the inductor to the output capacitors.
Use a separate trace from AGND to DGND, and use
DGND as the ground point for all the power components.
Use additional bypass capacitors at each termination
resistor pack.
DD
L
pins
A typical application circuit schematic is shown in Figure 2,
and a sample layout is shown in Figure 3.
Where L
in Figure 2, and 0.020 is the source resistance of the output
V
L
. Both L
DCR
and 0.020 are in Ohms.
DCR
is the DC resistance of the output inductor, L1
Manufacturer
Coiltronics
Part No.
UP3-4R7
Inductance
4.7μH
DC
Resistance
0.011
I
OUT MAX
)
DESIRED
--------------------------------------------------+
OUTPUT
DCR
–
(
)
V
TT
×
=
(1)
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ML6553CS1 | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 Bus Termination RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| ML6553CS-1 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Bus Termination Regulator |
| ML6553CS1X | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 Bus Termination RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| ML6554 | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:3A Bus Termination Regulator |
| ML65541 | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:High Speed Octal Buffer/Line Drivers |
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