AAT4625_06 Datasheet, PDF (7/15 Pages) Advanced Analogic Technologies – USB Single-Channel Power Switch

Functional Block Diagram
AAT4625
USB Single-Channel Power Switch
IN
Under-
voltage
Lockout
Over-Temperature
Protection
EN (EN)
1.2V
Reference
Current
Limit
GND
OUT
FLG
Functional Description
The AAT4625 is an integrated MOSFET load
switch with a fixed current limit, over-temperature
protection, level shifted input, and a fault flag.
The current limit control is combined with an over-
temperature thermal limit circuit to provide a com-
prehensive system to protect the load switch
under short-circuit or other adverse operating
conditions. The AAT4625 is ideally suited for con-
trol and protection of peripheral ports such as
USB, RS232, and parallel ports.
The current limit and over-temperature circuits will
act independently. The device current limit is acti-
vated when the output load current exceeds a pre-
set internal threshold level. The minimum current
limit threshold characteristic is specified by I_LIM(MIN).
If the load switch ambient temperature becomes
excessive or if a short-circuit condition persists, the
die temperature will rise, causing the over-temper-
ature protection circuit to activate.
If the current limit or over-temperature protection
circuits are active for more than two milliseconds,
the system will be informed via the FAULT flag. A
10ms fault blanking delay allows the AAT4625 to
be turned on into large capacitive loads without
activating the FAULT flag. The open drain FAULT
output can be connected directly to system con-
trollers driven by voltage levels less than the IN pin
voltage without additional level shifting circuitry.
The load switch is turned on and off by applying a
logic level signal to the EN pin. The AAT4625
enable function is available in both active high and
active low logic level versions. The AAT4625 typi-
cally consumes 16µA when operating; when off, the
device draws less than 1µA. In the off state, current
is prevented from flowing between the input and out-
put. The EN function has logic level thresholds that
allow the AAT4625 to be TTL compatible and may
also be controlled by 2.5V to 5.0V CMOS circuits.
The voltage level on either EN or FAULT should not
exceed the input supply level present on the IN pin.
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