MAX1553/MAX1554

High-Efficiency, 40V Step-Up

Converters for 2 to 10 White LEDs

Maxim Integrated | 9

www.maximintegrated.com

SUPPLIER

PHONE

WEBSITE

Central

Semiconductor

631-435-1110

www.centralsemi.com

Kamaya

260-489-1533

www.kamaya.com

Murata

814-237-1431

www.murata.com

Nichia

248-352-6575

www.nichia.com

Panasonic

714-373-7939

www.panasonic.com

Sumida

847-956-0666

www.sumida.com

Taiyo Yuden

408-573-4150

www.t-yuden.com

TDK

847-803-6100

www.component.tdk.com

TOKO

847-297-0070

www.toko.com

Table 1. Component Suppliers

LX

SS

FB

ON

OFF

BRT

GND

BATTERY

INPUT

C1

4.7

μF

C3

0.1

μF

C2

0.47

μF

OV

EN

WHITE

LEDs

C4

0.1

μF

3.3V

LOGIC

MAX1553

MAX1554

L1

D1

R2

R3

R1

Applications Information

Low Input-Voltage Applications

The MAX1553/MAX1554 have minimum input voltages

of 2.7V (MAX1553) and 3.15V (MAX1554). However,

lower battery voltages can still be boosted for LED

range. Since most systems have a 3.3V system supply

active when the display is active and backlit, that logic

power connects directly to the boost inductor. No bat-

tery current is drawn when EN is low (Figure 4).

PC Board Layout

Due to fast-switching waveforms and high-current

paths, careful PC board layout is required. An evalua-

tion kit (MAX1553EVKIT) is available as an example of

a proper layout.

When laying out a board, minimize trace lengths

between the IC and the inductor, diode, input capaci-

tor, output capacitor, and R1. Keep traces short, direct,

and wide. Keep noisy traces, such as the LX node

(C1) as close to the IC as possible. The ground con-

nections of C1 and C2 should be as close together as

possible. Star connect the grounds for R1, R3, C3, and

the BRT voltage supply as close to the IC as possible.

from the LEDs to R1 can be longer if required.

Chip Information

TRANSISTOR COUNT: 740

PROCESS: BiCMOS

Figure 4. The MAX1553/MAX1554 can drive LEDs from battery

voltages that are lower than the device operating voltage

the boost inductor to the battery.

Package Information

For the latest package outline information and land patterns (foot-

“+”, “#”, or “-” in the package code indicates RoHS status only.

Package drawings may show a different suffix character, but the

drawing pertains to the package regardless of RoHS status.

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE NO.

LAND

PATTERN NO.

TDFN-EP

T833-2

21-0137

90-0059