- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384654 > MAX1864UEEE (MAXIM INTEGRATED PRODUCTS INC) xDSL/Cable Modem Triple/Quintuple Output Power Supplies PDF資料下載
參數(shù)資料
| 型號： | MAX1864UEEE |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | xDSL/Cable Modem Triple/Quintuple Output Power Supplies |
| 中文描述： | 0.5 A SWITCHING CONTROLLER, 120 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 0.150 INCH, 0.025 INCH PITCH, QSOP-16 |
| 文件頁數(shù)： | 17/25頁 |
| 文件大?。?/td> | 384K |
| 代理商： | MAX1864UEEE |
M
xDSL/Cable Modem Triple/Quintuple Output
Power Supplies
______________________________________________________________________________________
17
Output Capacitor
The key selection parameters for the output capacitor
are the actual capacitance value, the equivalent series
resistance (ESR), and voltage-rating requirements,
which affect the overall stability, output ripple voltage,
and transient response.
The output ripple has two components: variations in the
charge stored in the output capacitor, and the voltage
drop across the capacitor
’
s ESR caused by the current
into and out of the capacitor:
The output voltage ripple as a consequence of the ESR
and output capacitance is:
where I
P-P
is the peak-to-peak inductor current (see
Inductor Selection
). These equations are suitable for
initial capacitor selection, but final values should be set
by testing a prototype or evaluation circuit. As a gener-
al rule, a smaller ripple current results in less output rip-
ple. Since the inductor ripple current is a factor of the
inductor value and input voltage, the output voltage rip-
ple decreases with larger inductance but increases
with lower input voltages.
With low-cost aluminum electrolytic capacitors, the
ESR-induced ripple can be larger than that caused by
the current into and out of the capacitor. Consequently,
high-quality low-ESR aluminum-electrolytic, tantalum,
polymer, or ceramic filter capacitors are required to
minimize output ripple. Best results at reasonable cost
are typically achieved with an aluminum-electrolytic
capacitor in the 470μF range, in parallel with a 0.1μF
ceramic capacitor.
Since the MAX1864/MAX1865 use a current-mode con-
trol scheme, the output capacitor forms a pole that
affects circuit stability (see
Compensation Design
).
Furthermore, the output capacitor
’
s ESR also forms a
zero.
The MAX1864/MAX1865s
’
response to a load transient
depends on the selected output capacitor. After a load
transient, the output instantly changes by ESR
I
LOAD
. Before the controller can respond, the output
will sag further, depending on the inductor and output
capacitor values.
After a short period of time (see
Typical Operating
Characteristics
), the controller responds by regulating
the output voltage back to its nominal state. For appli-
cations that have strict transient requirements, low-ESR
high-capacitance electrolytic capacitors are recom-
mended to minimize the transient voltage swing.
Do not exceed the capacitor
’
s voltage or ripple-current
ratings.
Compensation Design
The MAX1864/MAX1865 controllers use an internal
transconductance error amplifier whose output com-
pensates the control loop. Connect a series resistor
and capacitor between COMP and GND to form a pole-
zero pair. The external inductor, high-side MOSFET,
output capacitor, compensation resistor, and compen-
sation capacitor determine the loop stability. The induc-
tor and output capacitor are chosen based on
performance, size, and cost. Additionally, the compen-
sation resistor and capacitor are selected to optimize
control-loop stability. The component values shown in
the standard application circuits (Figures 1 and 6) yield
stable operation over a broad range of input-to-output
voltages.
The controller uses a current-mode control scheme that
regulates the output voltage by forcing the required
current through the external inductor, so the
MAX1864/MAX1865 use the voltage across the high-
side MOSFET
’
s R
DS(ON)
to sense the inductor current.
Using the current-sense amplifier
’
s output signal and
the amplified feedback voltage, the control loop deter-
mines the peak inductor current by:
V
I
ESR
V
I
C
I
V
V
L
V
V
RIPPLE ESR
p p
-
RIPPL( )
p p
-
OUT SW
p p
-
IN
OUT
SW
OUT
IN
(
)
=
=
=
-
2
V
V
V
RIPPLE
RIPPLE ESR
RIPPLE( )
=
+
(
)
BST
N
H
R
GATE
(OPTIONAL)
N
L
R
(OPTIONAL)
C
BST
DH
LX
L
TO VL
DH
GND
MAX1864
MAX1865
Figure 5. Reducing the Switching EMI
相關PDF資料 |
PDF描述 |
|---|---|
| MAX1865UEEP | xDSL/Cable Modem Triple/Quintuple Output Power Supplies |
| MAX1865TEEP | xDSL/Cable Modem Triple/Quintuple Output Power Supplies |
| MAX1864TEEE | xDSL/Cable Modem Triple/Quintuple Output Power Supplies |
| MAX1887 | Quick-PWM Slave Controllers for Multiphase, Step-Down |
| MAX1889EGE | Triple-Output TFT LCD Power Supply with Fault Protection |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1864UEEE-T | 功能描述:電流和電力監(jiān)控器、調(diào)節(jié)器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Current Regulators 電源電壓-最大:48 V 電源電壓-最小:5.5 V 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:HPSO-8 封裝:Reel |
| MAX1865TEEP | 功能描述:電流和電力監(jiān)控器、調(diào)節(jié)器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Current Regulators 電源電壓-最大:48 V 電源電壓-最小:5.5 V 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:HPSO-8 封裝:Reel |
| MAX1865TEEP+ | 功能描述:DC/DC 開關控制器 xDSL/Cable Modem Triple/Quint Output RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1865TEEP+T | 功能描述:電流和電力監(jiān)控器、調(diào)節(jié)器 xDSL/Cable Modem Triple/Quint Output RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Current Regulators 電源電壓-最大:48 V 電源電壓-最小:5.5 V 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:HPSO-8 封裝:Reel |
| MAX1865TEEP-T | 功能描述:電流和電力監(jiān)控器、調(diào)節(jié)器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Current Regulators 電源電壓-最大:48 V 電源電壓-最小:5.5 V 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:HPSO-8 封裝:Reel |
發(fā)布緊急采購，3分鐘左右您將得到回復。