Datasheet

TPS22907
www.ti.com SLVSA44A –NOVEMBER 2009–REVISED SEPTEMBER 2013
APPLICATION INFORMATION
On/Off Control
The ON pin controls the state of the switch. Asserting ON high enables the switch. 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 threshold. It can be used with any microcontroller with 1.2-V, 1.8-V, 2.5-V, or 3.3-V GPIOs.
Input Capacitor
To limit the voltage drop on the input supply caused by transient inrush 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-μF ceramic
capacitor, C
IN
, place close to the pins is usually sufficient. Higher values of C
IN
can be use to further reduce the
voltage drop during high-current application. When switching heavy loads, it is recommended to have an input
capacitor approximately ten times higher than the output capacitor to avoid excessive voltage drop.
Output Capacitor
Due to the integrated 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
. A CIN to CL ratio of at least 10 to 1 is recommended for
minimizing V
IN
dip caused by inrush currents during startup; however, a 10 to 1 ratio for capacitance is not
required for proper functionality of the device. A ratio smaller than 10 to 1 (such as 1 to 1) could cause slightly
more V
IN
dip at turn on due to inrush currents.
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 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.
Figure 24. Example Layout for the TPS22907
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