AOZ1321DI
Detailed Description
Internal Discharge Resistor
The AOZ1321DI has an internal 160Ω resistor to
discharge any remaining voltage from the system to
the ground that is store in a capacitive load. This provides
a safe shutdown of the system to prevent any damages
to the devices. This function is controlled from the
Enable pin.
Slew Rate Control
The AOZ1321DI is a family of P-channel high-side load
switches with controlled slew rate. The device is enabled
when the EN pin is high. Once enabled, the gate driver
and slew-rate control circuitry immediately raises the
source-to-gate voltage of the P-channel MOSFET to its
threshold level, and then gradually turns on the MOSFET
by linearly increasing the source-to-gate voltage. This
slow turn-on action effectively limits the input inrush
current and provides a nice ramp for the output voltage.
After the MOSFET is fully enhanced, the AOZ1321DI
quickly increases the source-to-gate voltage to the full
input voltage to minimize on resistance and reduce
power dissipation.
Three slew-rate options are available. AOZ1321DI-01L
and AOZ1321DI-04L have slew rate of 800us. This
option significantly reduces the inrush current when the
MOSFET turns on, allowing the use of very small input
capacitor. AOZ1321DI-02L and -05L have no slew rate
control and the MOSFET can be turned on within 1us.
This option is suitable for applications that require very
fast switching. AOZ1321DI-03L and -06L have moderate
slew rate to 100µs. The AOZ1321DI-03L, -04L and -05L
options include an internal output discharge circuit that
quickly discharges the output to ground when the device
is disabled.
On/Off Control
The AOZ1321DI is enabled when the EN pin is asserted
high. The device is disabled when the EN pin is asserted
low. The EN input is compatible with both TTL and CMOS
logic.
Applications Information
Input Capacitor Selection
Use a 1µF or larger capacitor for input bypassing.
Place the capacitor close to the IN pins of AOZ1321DI.
Output Capacitor Selection
Use a 0.1µF or larger capacitor between OUT and GND.
The capacitance does not affect the turn-on slew rate.
However, a larger capacitor makes the initial turn-on
transient smoother.
Rev. 1.1 August 2008
www.aosmd.com
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