Datasheet

TPS2500, TPS2501
SLVS886C –OCTOBER 2008–REVISED AUGUST 2010 www.ti.com
FAULT
FAULT is an open-drain output that indicates when the USB switch is in an overcurrent or overtemperature
condition. FAULT has a fixed internal deglitch of t
DEG
to prevent false triggering from noise or transient
conditions. FAULT asserts low if the USB switch remains in an overcurrent condition for longer than t
DEG
. FAULT
de-asserts when the overcurrent condition is removed after waiting for the same t
DEG
period. Overtemperature
conditions bypass the internal delay period and assert/de-assert the FAULT output immediately upon entering or
leaving an overtemperature condition. FAULT is asserted low when V
AUX
falls below V
TRIP
(4.6 V, typical).
GND
Signal and logic circuits of the TPS2500 are referenced to GND. Connect GND to a quiet ground plane near the
device. An optional 0.1-mF capacitor can be connected from V
IN
to GND close the device to provide local
decoupling. Connect GND and PGND to the thermal pad externally at a single location to provide a star-point
ground. See the Layout Recommendations section for further details.
ILIM
Connect a resistor from ILIM to GND to program the current-limit threshold of the USB switch. Place this resistor
as close to the device as possible to prevent noise from coupling into the internal circuitry. Do not drive ILIM with
an external source. The current-limit threshold is proportional to the current through the R
ILIM
resistor. See the
Programming the Current-Limit Threshold Resistor section for details on selecting the current-limit resistor.
IN
IN is the input voltage supply for the boost converter. Connect a 10-mF ceramic capacitor (minimum) from IN to
PGND. See the Component Recommendations section for further details on selecting the input capacitor.
PGND
PGND is the internal ground connection for the source of the low-side N-channel MOSFET in the boost
converter. Connect PGND to an external plane near the ground connection of the input and output capacitors to
minimize parasitic effects due to high switching currents of the boost converter. Connect PGND to GND and the
thermal pad externally at a single location to provide a star-point ground. See the Layout Recommendations
section for further details.
SW
SW is the internal boost converter connection of the low-side N-channel MOSFET drain and the high-side
P-channel drain. Connect the boost inductor from IN to SW close to the device to minimize parasitic effects on
the device operation.
Thermal Pad
The thermal pad connection is used to heat-sink the device to the printed-circuit board (PCB). The thermal pad
may not be connected externally to a potential other than ground because it is connected to GND internally. The
thermal pad must be soldered to the PCB to remove sufficient thermal energy in order to stay within the
recommended operating range of the device.
USB
USB is the output of the USB switch and should be connected to the USB connector to provide USB power.
Although the device does not require it for operation, a bulk capacitor may be connected from USB to PGND to
meet USB standard requirements. See the latest USB 2.0 specification for further details.
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