LP3875EMP-18 Datasheet, PDF (11/25 Pages) Texas Instruments – LP3872/LP3875 1.5A Fast Ultra Low Dropout Linear Regulators

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LP3872, LP3875
SNVS227F – FEBRUARY 2003 – REVISED APRIL 2013
Figure 19. Error Flag Operation
SENSE PIN
In applications where the regulator output is not very close to the load, LP3875 can provide better remote load
regulation using the SENSE pin. Figure 20 depicts the advantage of the SENSE option. LP3872 regulates the
voltage at the output pin. Hence, the voltage at the remote load will be the regulator output voltage minus the
drop across the trace resistance. For example, in the case of a 3.3V output, if the trace resistance is 100mΩ, the
voltage at the remote load will be 3.15V with 1.5A of load current, I_LOAD. The LP3875 regulates the voltage at the
sense pin. Connecting the sense pin to the remote load will provide regulation at the remote load, as shown in
Figure 20. If the sense option pin is not required, the sense pin must be connected to the V_OUT pin.
Figure 20. Improving Remote Load Regulation Using LP3875
SHUTDOWN OPERATION
A CMOS Logic level signal at the shutdown ( SD) pin will turn-off the regulator. Pin SD must be actively
terminated through a 10kΩ pull-up resistor for a proper operation. If this pin is driven from a source that actively
pulls high and low (such as a CMOS rail to rail comparator), the pull-up resistor is not required. This pin must be
tied to Vin if not used.
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