VIN

CIN

VIN

RON

RFBT

CFF

CSS

RFBB

COUT

LMZ14203H

VOUT

10PF

4700 pF

0.022 PF

* RENT

* RENB

* See equation 1

to calculate values

VOUT

RFBT

RFBB

RON

COUT

COUT-ESR

VIN

12V

34 k:

2.43 k:

249 k:

47 PF

1-45 m:

15 - 42V

15V

34 k:

1.91 k:

287 k:

47 PF

1-42 m:

18 - 42V

18V

34 k:

1.58 k:

374 k:

33 PF

1-40 m:

22 - 42V

24V

34 k:

1.18 k:

499 k:

33 PF

1-40 m:

28 - 42V

30V

34 k:

931:

619 k:

33 PF

1-45 m:

34 - 42V

5V

34 k:

6.49 k:

100 k:

100 PF

1-95 m:

8 - 42V

LMZ14203H

SNVS692G – JANUARY 2011 – REVISED OCTOBER 2015

www.ti.com

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 LMZ14203H is a step down DC-to-DC power module. It is typically used to convert a higher DC voltage to a

lower DC voltage with a maximum output current of 3 A. The following design procedure can be used to select

components for the LMZ14203H. Alternately, the WEBENCH software may be used to generate complete

designs.

When generating a design, the WEBENCH software uses iterative design procedure and accesses

comprehensive databases of components. For more details, go to www.ti.com.

8.2 Typical Application

Figure 46. Simplified Application Schematic

8.2.1 Design Requirements

For this example the following application parameters exist.

•

VIN Range = Up to 42 V

•

VOUT = 5 V to 30 V

•

IOUT = 3 A

Refer to the table in Figure 46 for more information.

8.2.2 Detailed Design Procedure

8.2.2.1 Design Steps for the LMZ14203H Application

The LMZ14203H is fully supported by WEBENCH which offers the following: component selection, electrical

simulation, thermal simulation, as well as a build-it prototype board for a reduction in design time. The following

list of steps can be used to manually design the LMZ14203H application.

1. Select minimum operating VIN with enable divider resistors.

2. Program VO with divider resistor selection.

3. Program turnon time with soft-start capacitor selection.

4. Select CO.

16

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