1

2

5

4

3

VIN

SW

FB

EN

GND

L1: 2.2 µH

10 µF

4.7 µF

LM3673-

ADJ

2.7 V to 5.5 V

R1

R2

C1

C2

1

2

5

4

3

VIN

SW

FB

EN

GND

L1: 2.2 µH

10 µF

4.7 µF

LM3673

2.7 V to 5.5 V

LM3673

www.ti.com

SNVS434L – JULY 2006 – REVISED OCTOBER 2015

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 LM3673 is designed for powering low-voltage circuits from a single Li-Ion cell battery and input-voltage rails

from 2.7 V to 5.5 V. The device is internally powered from the VIN pin, and the typical switching frequency is 2

MHz. The LM3673 is available in 1.2-V, 1.5-V, and 1.8-V options. An externally adjustable version is also

available where the output voltage can be set with an external resistor divider to the FB pin.

9.2 Typical Applications

Figure 17. LM3673 Typical Application Circuit

Figure 18. LM3673-ADJ Typical Application Circuit

9.2.1 Design Requirements

For typical step-down DC-DC converter applications, use the parameters listed in Table 1.

Table 1. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Minimum input voltage

2.7 V

Output voltage

several fixed options; adjustable

Maximum load current

350 mA

Switching frequency

2 MHz (typical)

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