Aug24-17 Rev M SP619 High Current Power Switch
4
THEORY OF OPERATION
The SP619 is a switch capable of handling
up to 800mA of current.
The SP619 is targeted as a 5V USB
protection power distribution switch. And
can be used in general power distribution
applications where short circuits are likely
to be encountered.
Short circuit operation
-
dition, the switch is disabled. The output
of the SP619 will not restart until the out-
enable pin can be used to re-enable the
SP619 into any load condition that is not a
fault condition. Refer to the truth table on
SP619 switch states. The typical deactiva-
tion time is about 2ms.
Enable
The enable pin allows easy control of
the SP619. The enable pin should not
be enabled high prior to a voltage being
present on the input of the device. The
enable pin should not exceed the in-
put voltage by more than 0.1V due to an
operation of the SP619 and could damage
enable pin. This resistor will pull the enable
low when an enable signal is not present.
This prevents the SP619 from falsely turn-
ing on. The enable pin can also be used
to restart the part into a load condition that
is high in current. Please refer to the truth
table on page 4 for more details.
Inrush Current
The SP619 is a simple resistive switch.
inrush current that can be encountered.
At 6 volts in, the inrush current was about
250mA into a 100µF capacitor.
Output Voltage Rise Time
The output voltage of the SP619 has an
output capacitance dependency on the
slope of V. A simple RC circuit is creat-
ed when the switch is turned on.
V(t)=V+V
(
(
R • C
-t
is initial Voltage condition typi-
cally 0V
V is the input voltage
R is the switch resistance
C is the output capacitance
For 4.2V V and 100µF output capacitance
4.17
3.33
2.5
1.67
0.83
000.33 0.67 11.33 1.67 2
time in uS
VOUT
This is comparable to actual measured
1-e