Datasheet

= - ´
VOUT VIN ON VOUT
V V R I
RSET
SET
200 k
R
I
W
=
TPS2421-1
TPS2421-2
www.ti.com SLUS907G –JANUARY 2009–REVISED MAY 2013
The internal MOSFET actively limits current if I
VIN
reaches the current limit set point. The fault timer operation is
the same in this mode as described previously.
The fault current value is programmed as shown in Equation 3:
(3)
EN: When this pin is pulled low, the device is enabled. The input threshold is hysteretic, allowing the user to
program a startup delay with an external RC circuit. EN is pulled to VIN with a 10-MΩ resistor and to GND with a
16.8 MΩ resistor. Because high impedance pullup/down resistors are used to reduce current draw, any external
FET controlling this pin should be low leakage.
VIN: Input voltage to the TPS2421. The recommended operating voltage range is 3 V to 20 V. Connect VIN to
the power source.
VOUT: Output connection for the TPS2421. V
VOUT
in the ON condition considering the ON resistance of the
internal MOSFET, R
ON
is shown in Equation 4:
(4)
Connect VOUT to the load.
PG: Active low, Open Drain output, Power Good indicates that there is no fault condition and the output voltage
is within 0.5 V of the input voltage. PG becomes operational before UV, whenever V
VIN
is greater than 1 V.
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