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參數(shù)資料
| 型號： | MAX14544ETA+T |
| 廠商： | Maxim Integrated |
| 文件頁數(shù)： | 8/10頁 |
| 文件大?。?/td> | 1137K |
| 描述： | IC ACCY SWITCH OVP PROTECT 8TDFN |
| 產(chǎn)品培訓(xùn)模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標(biāo)準(zhǔn)包裝： | 2,500 |
| 功能： | 電流開關(guān) |
| 輸入電壓： | 2.3 V ~ 5.5 V |
| 電流 - 輸出： | 可調(diào) |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 8-WFDFN 裸露焊盤 |
| 供應(yīng)商設(shè)備封裝： | 8-TDFN-EP（2x2） |
| 包裝： | 帶卷 (TR) |
28V-Capable, I
LIM
V
BUS
Accessory Switch
8
Detailed Description
The MAX14544/MAX14545 are overcurrent detection
switches that prevent host devices from being damaged
due to faulty load conditions. The switch opens if current
exceeds the current limit for longer than the blanking
time or if a reverse-current condition is detected. The
switch also disconnects if V
IN
exceeds OVLO, V
IN
falls
below UVLO, thermal shutdown occurs, or EN is driven
low. Current limit can be set to either 200mA or 400mA.
When the switch is open, the output (OUT) can withstand
28V maximum.
When the switch is on and a load is connected to the
port, a blanking time of 10.5ms ensures that the inrush
current settles down. After this blanking time, if the volt-
age across the switch is greater than the FLAG asser-
tion voltage, the part is turned off and issues a FLAG
to the microprocessor. After the retry time elapses, the
MAX14544 switch is closed for the duration of the blank-
ing time to check if the load current is lower than the
limit. Cycle the power or EN input to turn the MAX14545
switch back on.
Current-Limit Threshold
The MAX14544/MAX14545 ISET logic input sets the
desired minimum current-limit threshold to 200mA or
400mA. Connect ISET low for a 200mA current limit and
high for a 400mA current limit. If 400mA is selected as
the current limit, the input supply current at shutdown
can be reduced by connecting ISET to EN. This is due
to the fact that the device consumes the lower supply
current in ISET = low mode than in ISET = high mode.
Reverse-Current Protection
The MAX14544/MAX14545 monitor the reverse current
(V
OUT
to V
IN
) from exceeding the maximum I
DET
value.
If the reverse-current detection threshold is exceeded,
the switch turns off and FLAG is asserted without waiting
for t
BLANK
to elapse. This feature prevents excessive
reverse currents from flowing through the device.
FLAG Indicator
The MAX14544/MAX14545 feature a fault output (FLAG).
Whenever V
IN
- V
OUT
> V
FA
, the MAX14544 asserts
FLAG low after the blanking time and keeps it low until
the condition is removed. During this time, the switch
cycles on and off in the autoretry mode. When the condi-
tion is removed, FLAG deasserts and the switch turns
on (Figure 1). The MAX14545 asserts FLAG low after the
blanking time and turns the switch off when FLAG asser-
tion voltage is exceeded (Figure 2).
FLAG is an open-drain output and requires an external
pullup resistor. During shutdown (EN is low), the pull-
down on FLAG output is released to limit power dissipa-
tion. FLAG goes low when one of the following occurs:
1) The temperature exceeds the thermal shutdown tem-
perature, +150NC (typ).
2) The device is in current limit for more than the fault
blanking period.
3) The switch is in autoretry.
4) The reverse current limit is exceeded.
5) The input is over the OVLO.
Autoretry (MAX14544)
When the FLAG assertion voltage is exceeded, the
t
BLANK
timer begins counting (Figure 1). The timer resets
if the condition disappears before t
BLANK
has elapsed.
A retry time delay (t
RETRY
) is started immediately after
t
BLANK
has elapsed and during that time the switch is
turned off and FLAG is asserted. At the end of t
RETRY
,
the device is turned on again. If the fault still exists, the
cycle is repeated. If the fault is removed, the device
stays on and FLAG deasserts.
The autoretry feature saves system power in the case
of a continuous overcurrent or short-circuit condition.
During t
BLANK
, when the switch is on, the supply current
is at the current limit. During t
RETRY
, when the switch
is off, the current through the switch is zero. Instead
of observing the full load current, the device sees the
equivalent load current times duty cycle or:
I
SUPPLY
= I
LOAD
x t
BLANK
/(t
BLANK
+ t
RETRY
)
With a typical t
BLANK
= 10.5ms and typical t
RETRY
=
661.5ms, the duty cycle is 1.6%, resulting in a 98.4%
power savings over the switch being on the entire time.
Latchoff (MAX14545)
When the FLAG assertion voltage is exceeded, the
t
BLANK
timer begins counting. The device turns off after
the blanking time. The timer resets if the condition is
removed before the end of the blanking time. Reset the
device by toggling EN (Figure 2).
Fault Blanking
The MAX14544/MAX14545 feature a 10.5ms (typ) fault
blanking. Fault blanking allows current-limit faults,
including momentary short-circuit faults that occur when
plugging a capacitive load, and also ensures that no
fault is issued during power-up. When a load transient
causes the device to enter current limit, an internal coun-
ter starts. If the load-transient fault persists beyond the
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX14544EVKIT+ | 功能描述:模擬開關(guān) IC 28V-Capable ILIM VBUS Accessory Switch RoHS:否 制造商:Texas Instruments 開關(guān)數(shù)量:2 開關(guān)配置:SPDT 開啟電阻（最大值）:0.1 Ohms 切換電壓（最大）: 開啟時(shí)間（最大值）: 關(guān)閉時(shí)間（最大值）: 工作電源電壓:2.7 V to 4.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:DSBGA-16 |
| MAX14545ETA+T | 制造商:Maxim Integrated Products 功能描述:28V-CAPABLE ILIM VBUS ACCESSORY SWITCH - Tape and Reel |
| MAX14547AEUT+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX14547AEUT+T | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX14548AEEWL+T | 制造商:Maxim Integrated Products 功能描述:100MBPS, 16-CHANNEL LLTS - Tape and Reel |
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