aoz1341 Alpha & Omega Semiconductor, aoz1341 Datasheet - Page 9

• Manufacturer Part Number: aoz1341
• Description: Dual Channel Usb Switch
• Manufacturer: Alpha & Omega Semiconductor

Detailed Description
The AOZ1341 is a member of Alpha and Omega
Semiconductor’s dual channel power distribution switch
family intended for applications where heavy capacitive
loads and short-circuits are likely to be encountered. This
device incorporates 70 mΩ N-channel MOSFET power
switches for power-distribution systems that require
multiple power switches in a single package. Each switch
is controlled by a logic enable input. Gate drive is
provided by an internal charge pump designed to control
the power-switch rise and fall times to minimize current
surges during switching. The charge pump requires no
external components and allows operation from supplies
as low as 2.7 V.
Power Switch
The power switch is a N-channel MOSFET with a low
on-state resistance capable of delivering 1 A of
continuous current. Configured as a high-side switch,
the MOSFET will go into high impedance when disabled.
Thus, preventing current flow from OUT to IN and IN to
OUT.
Charge Pump
An internal charge pump supplies power to the circuits
and provides the necessary voltage to drive the gate of
the MOSFET beyond the source. The charge pump is
capable of operating down to a low voltage of 2.7 Volts.
Driver
The driver controls the voltage on the gate to the power
MOSFET switch. This is used to limit the large current
surges when the switch is being turned On and Off.
Proprietary circuitry controls the rise and fall time of the
output voltages.
Rev. 1.0 April 2011
www.aosmd.com
Enable
The logic enable disables the power switch, charge
pump, gate driver, logic device, and other circuitry to
reduce the supply current. When the enable receives a
logic high the supply current is reduced to approximately
1 μA. The enable input is compatible with both TTL and
CMOS logic levels.
Over-current
The over-current open drain output is asserted
(active low) when an over-current condition occurs.
The output will remain asserted until the over-current
condition is removed. A 15 ms deglitch circuit prevents
the over-current from false triggering.
Thermal Shut-down Protection
When the output load exceeds the current-limit threshold
the device limits the output current to a safe level by
switching into a constant-current mode, pulling the
overcurrent (OC) logic output low.
During current limit conditions the increasing power
dissipation in the chip causing the die temperature to
rise. When the die temperature reaches a specified level
the thermal shutdown circuitry will shutdown the device.
The thermal shutdown will cycle repeatedly until the short
circuit condition is resolved.
AOZ1341
Page 9 of 16