Datasheet

MIN
1.037
ILIMx
48000
IOS 2500mA
R
= =
1
1
1.037
1.037
ILIMx
MIN
48000 48000
R 17.28kΩ
IOS 2500mA
é ù
é ù
= = =
ê ú
ê ú
ë û
ë û
ILIMx
17.28kΩ
R 17.11kΩ
1.01
= =
ILIMx
R 16.9kΩ=
TPS2554
TPS2555
www.ti.com SLVSAM0 –JUNE 2011
Current Limit Setpoint Example
In the following example, choose the ILIM resistor to ensure that the TPS2554/55 does not trip off under
worst-case conditions of ILIM and resistor tolerance (assume 1% initial-plus-temperature resistor tolerance). For
this example IOS
MIN
= 2500 mA.
(5)
(6)
Including resistor tolerance, target maximum:
(7)
Choose:
(8)
Layout Guidelines
TPS2554/55 Placement: Place the TPS2554/55 near the USB output connector and 150-µF OUT pin filter
capacitor. Connect the exposed PowerPad™ to the GND pin and to the system ground plane using a via array.
IN Pin Bypass Capacitance: Place the 100-nF bypass capacitor near the IN and GND pins, and make the
connections using a low-inductance trace.
ILIM0 and ILIM1 Pin Connections: Current-limit, set-point accuracy can be compromised by stray current
leakage from a higher voltage source to the ILIM0 or ILIM1 pins. Ensure that there is adequate spacing between
IN pin copper/trace and ILIM0 pin trace to prevent contaminant buildup during the PCB assembly process. If a
low-current-limit set point is required (R
ILIMx
> 200 kΩ), use ILIM1 for this case as it is further away from the IN
pin.
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Product Folder Link(s): TPS2554 TPS2555