AIC6162 Datasheet, PDF (8/9 Pages) Analog Intergrations Corporation – 0.75A Single Channel USB Switch

AIC6162
 APPLICATION INFORMATION
 Flag Output
An error Flag is an open-drained output of an
N-channel MOSFET. Flag output is pulled low to
signal the following fault conditions: input
undervoltage, output current limit, and thermal
shutdown. The current limit flag response delay
time is 9ms.
 Current Limit
The current limit threshold is preset internally. It
protects the output MOSFET switches from
damage resulting from undesirable short circuit
conditions or excess inrush current, which is
often encountered during hot plug-in. The error
flag signals when any current limit conditions
occur.
 Thermal Shutdown
When temperature of AIC6162 exceeds 145C
for any reasons, the thermal shutdown function
turns MOSFET switch off and signals the error
flag. A hysteresis of 20C prevents the
MOSFETs from turning back on until the chip
temperature drops below 125C.
 Enable Control
Enable must be driven logic high or logic low for a
clearly defined input. Floating the input may cause
unpredictable operation.
 Under-voltage Lockout
UVLO (undervoltage lockout) prevents the
output MOSFET from turning on until input
voltage exceeds 2.3V typically. After the switch
turns on, if the input voltage drops below 2.1V
typically, UVLO shuts off the output MOSFET.
 Supply Filtering
A 1F bypass capacitor from USB IN to GND,
located near the device, is strongly
recommended to control supply transients.
Without a bypass capacitor, an output short may
cause sufficient ringing on the input (from supply
lead inductance) to damage internal control
circuitry.
 Transient Requirements
USB supports dynamic attachment (hot plug-in)
of peripherals. A current surge is caused by the
input capacitance of downstream device. Ferrite
beads are recommended in series with all power
and ground connector pins. Ferrite beads
reduce EMI and limit the inrush current during
hot-attachment by filtering high-frequency
signals.
 Short Circuit Transient
Bulk capacitance provides the short-term
transient current needed during a
hot-attachment event. A 22F/10V ceramic
capacitor mounted close to downstream
connector each port should provide transient
drop protection.
 Printed Circuit Layout
The power circuitry of USB printed circuit boards
requires a customized layout to maximize
thermal dissipation and to minimize voltage drop
and EMI.
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