VIN

EN

VCC

AGND

PGND

SW

BOOT

FB

L

4.7uF

22 µF

6.8 µH

0.1 µF

1 µF

100 NŸ

24.9 NŸ

6 V to 36 V

PG

PG

100 NŸ

220 nF

220 nF

2x 47 µF

5 V

4 A

16

LM60440, LM60430

SNVSBN5A – FEBRUARY 2020 – REVISED JUNE 2020

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Product Folder Links: LM60440 LM60430

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Copyright © 2020, Texas Instruments Incorporated

9 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.

9.1 Application Information

The LM604x0 step-down DC-to-DC converter is typically used to convert a higher DC voltage to a lower DC

voltage with a maximum output current of 4 A. The following design procedure can be used to select components

for the LM604x0. Alternately, the WEBENCH Design Tool can be used to generate a complete design. This tool

utilizes an iterative design procedure and has access to a comprehensive database of components. This allows

the tool to create an optimized design and allows the user to experiment with various options.

NOTE

In this data sheet, the effective value of capacitance is defined as the actual capacitance

under D.C. bias and temperature; not the rated or nameplate values. Use high-quality,

low-ESR, ceramic capacitors with an X5R or better dielectric throughout. All high value

ceramic capacitors have a large voltage coefficient in addition to normal tolerances and

temperature effects. Under D.C. bias the capacitance drops considerably. Large case

sizes and/or higher voltage ratings are better in this regard. To help mitigate these effects,

multiple capacitors can be used in parallel to bring the minimum effective capacitance up

to the required value. This can also ease the RMS current requirements on a single

capacitor. A careful study of bias and temperature variation of any capacitor bank should

be made in order to ensure that the minimum value of effective capacitance is provided.

9.2 Typical Application

Figure 9 shows a typical application circuit for the LM604x0. This device is designed to function over a wide

range of external components and system parameters. However, the internal compensation is optimized for a

certain range of external inductance and output capacitance. As a quick start guide, Table 2 and Table 3 provide

typical component values for a range of the most common output voltages. The values given in the table are

typical. Other values can be used to enhance certain performance criterion as required by the application. Note

that for the WQFN package, the input capacitors are split and placed on either side of the package; see the Input

Capacitor Selection section for more details.

Figure 9. Example Application Circuit (400 kHz)