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参数资料
| 型号： | MAX1838EEE |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 电源管理 |
| 英文描述： | Dual USB Switch with Fault Blanking and Autoreset |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO16 |
| 封装： | 0.150 INCH, 0.025 INCH PTICH, QSOP-16 |
| 文件页数： | 10/12页 |
| 文件大小： | 639K |
| 代理商： | MAX1838EEE |
M
between IN and AUX. However, a fault does not trigger
since the fault blanking-time is longer than the supply
switchover time.
Applications Information
Input Power Source
AUX provides the power for the MAX1838 internal con-
trol circuitry. Limit the input-voltage slew rate to less
than 0.2V/μs to prevent erroneous
FAULT
indications.
Input Capacitor
To limit the input voltage drop during momentary output
short-circuit conditions, connect a capacitor from both
AUX and IN to ground. A 0.1μF ceramic capacitor is
required for local decoupling; however, higher capaci-
tor values will further reduce the voltage drop at the
input (Figure 2). When driving inductive loads, a larger
capacitance prevents voltage spikes from exceeding
the MAX1838
’
s absolute maximum ratings.
Output Capacitor
An output capacitor helps prevent parasitic inductance
from pulling OUT negative during turn-off. When start-
ing up into very large capacitive loads, the switch puls-
es the output current at 0.35A
RMS
until the output
voltage rises above 1V, then the capacitor continues to
charge at the full 0.9A current limit. There is no limit to
the size of output capacitor, but to prevent a startup
fault assertion, the capacitor must charge up within the
fault-blanking delay period. Typically starting up into a
330μF or smaller capacitor does not trigger a fault out-
put. In addition to bulk capacitance, small value (0.1μF
or greater) ceramic capacitors improve the output
’
s
resilience to electrostatic discharge (ESD).
Driving Inductive Loads
A wide variety of devices (mice, keyboards, cameras,
and printers) can load the USB port. These devices
commonly connect to the port with cables, which can
add an inductive component to the load. This induc-
tance causes the output voltage at the USB port to ring
Dual USB Switch with Fault Blanking
and Autoreset
10
______________________________________________________________________________________
CONDITION
MAX1838 BEHAVIOR
If a short circuit is present
(V
OUT
< 1V)
If a short circuit is detected at the output, the channel turns off, the blanking timer
begins, and
FAULT
stays high.
If the short circuit persists during the fault-blanking period, the output pulses at 0.35A
-
RMS
. When the short is removed before the 15ms short-circuit blanking timeout period,
the next ramped current pulse soft-starts the output. The
FAULT
flag stays high.
If the short circuit persists after the fault-blanking period,
FAULT
goes low, autoreset
mode is enabled, and the output sources 25mA. If the voltage on that output is above
0.5V for 20ms, the channel resets, the output turns on, and
FAULT
goes high (see
Short-Circuit Response
in the
Typical Operating Characteristics.
)
If an overload current is present
(V
OUT
> 1V)
Output current regulates at I
LIM
, the blanking timer turns on, and
FAULT
stays high.
Continuous current at I
LIM
persists until the overload is removed, a thermal fault occurs,
or the 20ms continuous current-limit timeout period is reached.
If overcurrent is still present at 20ms,
FAULT
goes low, autoreset mode is enabled, and
the output sources 25mA. If the voltage on that output is above 0.5V for 20ms, the
channel resets, the output turns on, and
FAULT
goes high.
If thermal fault condition is present
FAULT
immediately goes low (the blanking timer does not apply to thermal faults), and
the channel turns off. When the junction cools by 15
o
C, the thermal fault condition is
removed, autoreset mode is enabled, the output sources 25mA, and
FAULT
remains
low. If the voltage on that output is above 0.5V for 20ms, the channel resets, the output
turns on, and
FAULT
goes high.
Table 2. MAX1838 Current Limiting and Fault Behavior
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1838EEE+ | 功能描述:电源开关 IC - USB Dual USB Switch w/Fault Blank RoHS:否 制造商:Micrel 电源电压-最小:2.7 V 电源电压-最大:5.5 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:SOIC-8 封装:Tube |
| MAX1838EEE+T | 功能描述:电源开关 IC - USB Dual USB Switch w/Fault Blank RoHS:否 制造商:Micrel 电源电压-最小:2.7 V 电源电压-最大:5.5 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:SOIC-8 封装:Tube |
| MAX1838EEE-T | 功能描述:电源开关 IC - USB Dual USB Switch w/Fault Blank RoHS:否 制造商:Micrel 电源电压-最小:2.7 V 电源电压-最大:5.5 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:SOIC-8 封装:Tube |
| MAX1839EEP | 功能描述:显示驱动器和控制器 RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX1839EEP+ | 功能描述:显示驱动器和控制器 CCFL Backlight Controller RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
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