500mV to 5.5V Input, Ultrasonic

Boost Converter with Short-Circuit

Protection and True Shutdown

MAX18002

www.analog.com

Analog Devices | 14

SHORT

VOUT

ILX

IPEAK_LX = 3.6A

(TYPICAL)

ISC = 0.7A

(TYPICAL)

Figure 4. Short-Circuit Operation

Applications Information

Inductor Selection

Select an inductor with a saturation current rating (ISAT) greater than or equal to the maximum high-side switching current

limit threshold (ILIM) setting. In general, inductors with lower saturation current and higher DC resistance (DCR) ratings

are physically small. Higher values of DCR reduce converter efficiency. Choose RMS current rating (IRMS) of the inductor

(the current at which the temperature rises appreciably) based on the expected load current.

The chosen inductor value should ensure that the peak-inductor ripple current (IPEAK) is below the ILIM setting so that the

converter can maintain regulation. The inductors recommended for different ranges of output voltages are shown in Table

2.

Table 2. Inductor and Output Capacitance Values vs Output Voltage

OUTPUT VOLTAGE (V)

RECOMMENDED INDUCTOR (nH)

EFFECTIVE OUTPUT CAPACITANCE

(µF)*

5

470

9

3.3–5

330

20

2.5–3.3

220

20

*The effective capacitance for all voltage levels can be achieved using 2 x 22µF, X5R, 0603 capacitors.

Table 3. Recommended Inductors

VENDOR

PART NUMBER

NOMINAL

INDUCTANCE

(nH)

TYPICAL

DCR (mΩ)

ISAT

(A)

IRMS

(A)

DIMENSIONS

(L x W x H (mm))

OUTPUT

VOLTAGE

(V)

Murata

DFE201612E-R47M

470

26

5.5

4.5

2.0 x 1.6 x 1.2

5

Taiyo

Yuden

MEKK2016HR47M

470

26

6.1

4.7

2.0 x 1.6 x 1.0

5

Murata

DFE201612E-R33M

330

21

6.3

4.8

2.0 x 1.6 x 1.2

3.3

Bourns

SRP2010TMA-R33M

330

29

5.0

3.8

2.0 x 1.6 x 1.0

3.3

Vishay

IHHP0806ABERR22M01

220

13

5.8

5.3

2.0 x 1.6 x 1.2

2.5

Taiyo

Yuden

MAKK2016HR22M

220

26

5.8

4

2.0 x 1.6 x 1.0

2.5