AAT4620_12 Datasheet, PDF (9/14 Pages) Skyworks Solutions Inc. – PCMCIA Current Limit Interface and Capacitor Charger

DATA SHEET
AAT4620
PCMCIA Current Limit Interface and Capacitor Charger
Functional Block Diagram
VCC
Reverse
Blocking
OUT
EN IL
EN IU
Under-
Voltage
Lockout
Over-Temp
Protection
Power
Loop
RDY
1.2V
Reference
Current Limit
Control
ISETL
ISETU
GND
RHYS
Functional Description
The AAT4620 is an integrated P-channel MOSFET load
switch with an upper and lower adjustable current limits
which can be enabled independently, over-temperature
protection, a power loop and a super capacitor charger.
The current limit control is combined with an over tem-
perature thermal limit and power loop circuit to provide
a comprehensive system to protect the load switch and
its supply from load conditions which exceed the supply
specifications. The AAT4620 has been designed specifi-
cally to provide the interface between a PCMCIA host
and PCMCIA card where a super capacitor has been used
to “average out” high pulse currents which would other-
wise exceed the PCMCIA/ Express Card power specifica-
tions. e.g. GSM/ GPRS modem cards, where pulse cur-
rents during transmit signals can exceed the 1A maxi-
mum specification (1.3A in the case of Express Card).
The current limit and over temperature circuits act inde-
pendently. The device current limit is activated when the
output load current exceeds an internal threshold level.
There are two internal current limits which are enabled
independently. The current limit threshold in each case
is determined by external resistors connected between
the two SET pins and ground. The minimum current limit
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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201943A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 15, 2012