APPLICATION INFORMATION

0.01 µF

4.7µF

4.7µF

Vin7V

28V

–

0.01 F

0.1 F

332k

68.1k

47pF

0

47 µF

Vout3.3V

IoutMax3 A

6.8 µH

10.2k

3.24k

29.4k

1000pF

47 µF

STEP BY STEP DESIGN PROCEDURE

SWITCHING FREQUENCY

TPS54331

Figure 13. Typical Application Schematic

The following design procedure can be used to select component values for the TPS54331. Alternately, the

SwitcherPro™Software may be used to generate a complete design. The SwitcherPro™ Software uses an

iterative design procedure and accesses a comprehensive database of components when generating a design.

This section presents a simplified discussion of the design process.

To begin the design process a few parameters must be decided upon. The designer needs to know the following:

• Input voltage range

• Output voltage

• Input ripple voltage

• Output ripple voltage

• Output current rating

• Operating frequency

For this design example, use the following as the input parameters

Table 3. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Input voltage range

7 V to 28V

Output voltage

3.3 V

Input ripple voltage

300 mV

Output ripple voltage

30 mV

Output current rating

3 A

Operating Frequency

570 kHz

The switching frequency for the TPS54331 is fixed at 570 kHz.

10

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