LP3872, LP3875

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SNVS227H – FEBRUARY 2003 – REVISED JANUARY 2015

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LP387x devices are linear regulators designed to provide high load current of up to 1.5 A, low dropout

voltage, and low quiescent current in shutdown mode. Figure 12 and Figure 13 show the typical application

circuit for these devices.

8.1.1 Dropout Voltage

The dropout voltage of a regulator is defined as the minimum input-to-output differential required to stay within

2% of the nominal output voltage. For CMOS LDOs, the dropout voltage is the product of the load current and

8.1.2 Reverse Current Path

The internal MOSFET in LP3872 and LP3875 has an inherent parasitic diode. During normal operation, the input

voltage is higher than the output voltage and the parasitic diode is reverse biased. However, if the output is

pulled above the input in an application, then current flows from the output to the input as the parasitic diode gets

forward biased. The output can be pulled above the input as long as the current in the parasitic diode is limited to

200-mA continuous and 1-A peak.

8.2 Typical Application

*SD and ERROR pins must be pulled high through a 10-k

Ω pullup resistor. Connect the ERROR pin to ground if this

function is not used. See the Shutdown Mode and ERROR Flag Operation sections.

Figure 12. LP3872 Typical Application Circuit

*SD must be pulled high through a 10-k

Ω pullup resistor. See the Shutdown Mode section.

Figure 13. LP3875 Typical Application Circuit

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Product Folder Links: LP3872 LP3875