LTC3410ESC6-1.8 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC3410ESC6-1.8

2.25MHz, 300mA Synchronous Step-Down Regulator in SC70

Linear Technology 

LTC3410

APPLICATIO S I FOR ATIO

Substituting VOUT = 3V, VIN = 4.2V, ∆IL = 100mA

and f = 2.25MHz in Equation (3) gives:

L

=

2.25MH3zV(100mA)⎛⎝⎜1−

3V

4.2V

⎞⎠⎟

=

3.8µH

A 4.7µH inductor works well for this application. For best

efficiency choose a 350mA or greater inductor with less

than 0.3Ω series resistance.

CIN will require an RMS current rating of at least 0.125A ≅

ILOAD(MAX)/2 at temperature and COUT will require an ESR

of less than 0.5Ω. In most cases, a ceramic capacitor will

satisfy this requirement. From Table 2, Capacitance Selec-

tion, COUT = 10µF and CIN = 4.7µF.

For the feedback resistors, choose R1 = 301k. R2 can

then be calculated from equation (2) to be:

R2 = ⎛⎝⎜

VOUT

0.8

− 1⎞⎠⎟ R1= 827.8k;use

825k

Figure 6 shows the complete circuit along with its

efficiency curve.

100

90

80

70

60

50

40

30

20

10

0

0.1

VIN

2.7V

TO 4.2V

CIN††

4.7µF

CER

4

VIN

3

SW

LTC3410

1

RUN

6

VFB

GND

2, 5

4.7µH*

10pF

VOUT

3V

COUT†

10µF

CER

825k

301k

3410 F06a

†TAIYO YUDEN JMK212BJ106

††TAIYO YUDEN JMK212BJ475

*MURATA LQH32CN4R7M23

Figure 6a

VOUT

100mV/DIV

AC COUPLED

IL

200mA/DIV

VIN = 3.6V

VIN = 4.2V

1

10

100

ILOAD (mA)

1000

3410 F06b

Figure 6b

ILOAD

200mA/DIV

20µs/DIV

VIN = 3.6V

VOUT = 3V

ILOAD = 100mA TO 300mA

Figure 6c

3410 F06c

3410fb

13

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