AIC1521
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PIN DESCRIPTION
MSOP8, SO8
PIN 1/4/6/8: NC:
PIN 2: CTL
- TTL compatible control input. It
controls the power switch turn-
on/turn-off.
Active High for
AIC1521-1 and active low for
AIC1521-0.
Power supply input.
Chip power ground.
SOT89-5
PIN 1: IN
PIN 2: GND
PIN 3: OUT
PIN 4: NC
PIN 5: CTL
- TTL compatible control input. It
controls the power switch turn-
on/turn-off.
Active High for
AIC1521-1 and active low for
AIC1521-0.
- Power supply input.
- Chip power ground.
- MOSFET switch output.
PIN 3: IN-
PIN 4: GND-
PN 7: OUT- MOSFET switch output.
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APPLICATION INFORMATIONS
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Current Limit
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Transient Droop Requirements
USB support 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.
The current limit threshold is preset internally. It
protects the output MOSFET switches from
damage due to undesirable short circuit
conditions or excess inrush current often
encountered during hot plug-in. The AIC1521
allows minimum 500mA continuous load current
per Channel.
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Thermal Protection
When the chip temperature exceeds 1
10°C, the
thermal protection function works.
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Short Circuit Transient
Bulk capacitance provides the short-term transient
current needed during a hot-attachment event. With
a 33uF, 16V tantalum or 100uF, 10V electrolytic
capacitor mounted close to downstream connector
should provide transient drop protection.
Supply Filtering
A 0.1uF to 1uF bypass capacitor from 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.
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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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AIC [ ANALOG INTERGRATIONS CORPORATION ]
