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參數(shù)資料
| 型號： | MAX878 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | DC/DC變換器 |
| 英文描述： | Adjustable-Output, DC-DC Converters(3.3V/3V輸出,1.8V~6V輸入,步升/步降DC-DC變換器) |
| 中文描述： | 可調輸出，DC - DC轉換（3.3V/3V輸出，電壓為1.8V?6V的輸入，步升/步降型DC - DC變換器） |
| 文件頁數(shù)： | 7/12頁 |
| 文件大小： | 152K |
| 代理商： | MAX878 |
With ILIM shorted to IN, the peak switch current of the
internal NPN power switch is set to 1A. It can be set to
a lower value by connecting a resistor between ILIM
and IN (see Current Limitsection). This enables the use
of physically smaller inductors with lower saturation-
current ratings. At 1A, the switch voltage drop (V
SW
) is
about 500mV. V
SW
decreases to about 250mV at 0.1A.
Conventional PWM converters generate constant-
frequency switching noise, while this architecture
produces variable-frequency switching noise. The out-
put ripple is the product of the peak inductor current
and the output capacitor's ESR. Unlike conventional
pulse-skippers, the MAX877/MAX878/MAX879 peak
currents are scaled down at light loads, resulting in
lower output ripple.
S tep-Down Mode and Power Dissipation
In battery-powered applications, for example, where
the input voltage exceeds the output voltage, the
MAX877/MAX878/MAX879 behave as “switched” linear
regulators. If the output voltage starts to drop, the
switch turns on and energy is stored in the coil, as in
normal step-up mode. After the switch turns off, the
voltage at LX flies high. The active rectifier turns on
when LX rises above V
IN
. As in a linear regulator, the
voltage difference between V
IN
and V
OUT
appears
across the rectifier (actually a PNP transistor) until the
current goes to zero and the rectifier turns off. At high
V
IN
to V
OUT
differentials, the maximum load current is
limited by the maximum allowable power dissipation in
the package (see Typical Operating Characteristics).
M
5V /3.3V /3V /Adjustable-Output,
S tep-Up/S tep-Down DC-DC Converters
_______________________________________________________________________________________
7
MAX878
DELAY
TIMER
t
OFF
DELAY
TIMER
t
ON
VREF
0.2025V
SHUTDOWN
CONTROL
SHDN
7
ACTIVE RECTIFIER
RECTIFIER
CONTROL
OUT
PGND
AGND
3
SEL 8
4
6
100
μ
F
V
OUT
22
μ
F
V
IN
22
μ
H
R
LIM
SWITCH
DRIVER
LX
ILIM
IN
2
1
5
1 : N
Figure 1. MAX878 Block Diagram
相關PDF資料 |
PDF描述 |
|---|---|
| MAX879 | Adjustable-Output, DC-DC Converters(3.3V/3V輸出,1.8V~6V輸入,步升/步降DC-DC變換器) |
| MAX883 | 5V or Adjustable, Low-Dropout, Low IQ, 200mA Linear Regulators(5V/可調,250mA,具有關閉方式的,P型溝道低壓差線性穩(wěn)壓器) |
| MAX882 | 3.3V or Adjustable, Low-Dropout, Low IQ, 200mA Linear Regulators(3.3V/可調,250mA,具有維持方式,P溝道低壓差線性穩(wěn)壓器) |
| MAX8862 | Low-Cost, Low-Dropout, Dual Linear Regulator |
| MAX8862_ESE | RES 160K OHM 1/16W 5% 0402 SMD |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX8782ETJ+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX8783GTC+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX8783GTC+T | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX8784ETL+ | 功能描述:顯示驅動器和控制器 Reg, CP, Op Amp for TFT LCDs RoHS:否 制造商:Panasonic Electronic Components 工作電源電壓:2.7 V to 5.5 V 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Reel |
| MAX8784ETL+T | 功能描述:顯示驅動器和控制器 Reg, CP, Op Amp for TFT LCDs RoHS:否 制造商:Panasonic Electronic Components 工作電源電壓:2.7 V to 5.5 V 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Reel |
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