AIC1525 查看數據表（PDF） - Analog Intergrations
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AIC1525 Datasheet PDF : 10 Pages
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n PIN DESCRIPTION
PIN 1: CTL
- TTL compatible control input. It
controls the power switch turn-
on/turn-off. Active High for
AIC1525-1 and active low for
AIC1525-0.
PIN 2: FLG
- An active-low and open-drain fault
flag output for power switch. It can
indicate current limit if CTL is
AIC1525
active. In normal mode operation,
it also can indicate thermal
shutdown or undervoltage.
PIN 3: GND - Chip power ground.
PIN 4: NC - Not internally connected.
PIN 5, 7: IN - Power supply Input.
PIN 6, 8: OUT - MOSFET switch output.
n APPLICATION INFORMATIONS
l Error Flag
An open-drained output of an N-channel MOSFET,
the FLG output is pulled low to signal the following
fault conditions: input undervoltage, output current
limit, and thermal shutdown.
l Current Limit
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 low limit of the current limit threshold of the
AIC1525 allows a minimum current of 0.5A through
the MOSFET switches. A current limit condition will
signal the error flag.
l Thermal Shutdown
When the chip temperature exceeds 135°C, the
thermal shutdown function turns off MOSFET switch
and signals the error flag. A hysteresis of 10°C
prevents the MOSFET from turning back on until the
chip temperature drops to below 125°C.
l Supply Filtering
A 0.1µF to 1µF 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.
l 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.
l Short Circuit Transient
Bulk capacitance provides the short-term transient
current needed during a hot-attachment event. With
a 33µF, 16V tantalum or 100µF, 10V electrolytic
capacitor mounted close to downstream connector
should provide transient drop protection.
l 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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