LP3871, LP3874

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SNVS225H – FEBRUARY 2003 – REVISED JUNE 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 must

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LP3871 and LP3874 devices are linear regulators designed to provide high load current of up to 0.8 A, low

dropout voltage, and low quiescent current in shutdown mode.

8.1.1 Reverse Current Path

The internal MOSFET in LP3871 and LP3874 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.

8.1.2 Turnon Characteristics for Output Voltages Programmed To 2 V or Below

As VIN increases during start-up, the regulator output will track the input until VIN reaches the minimum operating

voltage (typically about 2.5 V). For output voltages programmed to 2 V or below, the regulator output may

momentarily exceed its programmed output voltage during start-up. Outputs programmed to voltages above 2 V

are not affected by this behavior.

8.2 Typical Applications

*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.

Figure 11. LP3871 Typical Application

*SD must be pulled high through a 10-k

Ω pullup resistor.

Figure 12. LP3874 Typical Application

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Product Folder Links: LP3871 LP3874