XRP2524EVB Datasheet, PDF (8/10 Pages) Exar Corporation – 1ADual Channel USB 3 .0 Power Distribution Switch

XRP2 52 4
1 A D u a l Ch a n n e l USB 3 .0 Po w e r D i st r i b u t i o n Sw i t ch
APPLICATION INFORMAT ION
The XRP2524 device is a dual channel
integrated high - side power distribution switch
that can be used in any self or bus powered
USB applications. It is compliant with the
latest USB 3.0 specifications.
The reverse
current protection feature prevents current to
flow from OUT to IN whe n the device is
disabled.
condition persists continuously for lon ger than
the blanking time of 9 ms typ ical . The blanking
time prevents erroneous reporting of current
faults due to brief output current spikes.
Once activated, t he err or flag signal remains
low until all fault condi tions have been
removed.
CURRENT LIMIT
I NPUT & OUTPUT
The current limit threshold is preset internally.
It pro tects the output MOSFET switch from
It is important WR SODFH DNj) FHUD^daP^mL^agF^e ^s E^re\^suS^ltD^ingVV^fro^{m undesirable short}
capacitor from IN to GND as close as possible
circuit conditions or excess inrush
current,
to the device in order to control supply
which is often encountered during hot plug -in.
transients. A high capacitor value and short
The low limit of the current limit threshold of
wires from power supply to VIN
can further
the XRP2524 allows a minimu m current of 1 A
reduce voltage droop on the input.
through the MOSFET switch .
Placing bulk capacitance of at least 22 Nj)at
An over - current condition is detected once the
the output pin reduces power supply
current limit threshold is exceeded , and output
transients under heavy current load
current is then limited to a constant current
conditions.
value . Triggering t he current limit function is
signaled by the Error Flag
Furthermore, bypassing the output pin with a
blanking time period.
Nj)WRNj)FHUDplaPcLedFclosFe Dto SDFLWRU
after 9 ms of
OUT and PGND improves the device response
to short - circuit transients.
UNDER - V OLTAGE LOCKOUT
Under - voltage lockout function (UVLO) keeps
ENABLE CONTROL
the internal power switch from being turned
The device is disa bled when the e nable pin is
in logic low condition. During this condition,
the internal circuitry and the switch are turned
off thereby red ucing the supply current to
0.1µA typical. Enable must be driven logic
on until the power supply exceeds 2.3 V
typically , even if the switch is enabled. Upon
detection of an input voltage below
approximately 2.1 V, the power switch is
turned off.
high for a clearly defined input. Floating the
input may cause unpredictable operation.
THERMAL PROTECTION
Internal thermal sensing circuitry monitors the
ERROR FLAG
operating temperature of the device. Upon
The error flag signal (FLG output pin) is an
open - drain output and is pulled low (active
low) upon detection of the following
fault
conditions:
detection of a temperature in excess of 14 5°C,
the power switch is disabled preventing any
damages to the device while a fault condition
is r eported by the error flag signal. A built -in
30°C hysteresis allows the device to cool down
x Over - current condition
to 1 30°C before resuming normal operation
by
x Over -temperature condition
turning the switch on. A t this time, the error
x Short - circuit condition
flag signal is cleared.
Over ±current, over -temperature and short -
circuit condition s are reported only if the
© 2012 Exar Corporation
8/ 10
Rev. 1.0.0