Datasheet

TPS22903
TPS22904
SLVS827C –FEBRUARY 2009–REVISED APRIL 2010 www.ti.com
APPLICATION INFORMATION
ON/OFF Control
The ON pin controls the state of the switch. Activating ON continuously holds the switch in the on state as there
is no fault. ON is active-high and has a low threshold, making it capable of interfacing with low-voltage signals.
The ON pin is compatible with standard GPIO logic thresholds. It can be used with any microcontroller with
1.2-V, 1.8-V, 2.5-V, or 3.3-V GPIOs.
Input Capacitor (Optional)
To limit the voltage drop on the input supply caused by transient in-rush currents when the switch turns on into a
discharged load capacitor or short-circuit, a capacitor needs to be placed between V
IN
and GND. A 1-mF ceramic
capacitor, C
IN
, placed close to the pins, is usually sufficient. Higher values of C
IN
can be used to further reduce
the voltage drop during high-current application. When switching heavy loads, it is recommended to have an
input capacitor about 10 times higher than the output capacitor to avoid excessive voltage drop.
Output Capacitor (Optional)
Due to the integral body diode in the PMOS switch, a C
IN
greater than C
L
is highly recommended. A C
L
greater
than C
IN
can cause V
OUT
to exceed V
IN
when the system supply is removed. This could result in current flow
through the body diode from V
OUT
to V
IN
.
Board Layout
For best performance, all traces should be as short as possible. To be most effective, the input and output
capacitors should be placed close to the device to minimize the effects that parasitic trace inductances may have
on normal and short-circuit operation. Using wide traces for V
IN
, V
OUT
, and GND helps minimize the parasitic
electrical effects along with minimizing the case-to-ambient thermal impedance.
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