40

60

50

80

70

90

100

010

515

20

EFFICIENCY vs. LED CURRENT

(vs. NUMBER of LEDs)

LED CURRENT (mA)

2 LEDs

4 LEDs

6 LEDs

40

60

50

80

70

90

100

010

515

20

EFFICIENCY vs. LED CURRENT

(vs. INPUT VOLTAGE)

LED CURRENT (mA)

40

60

50

80

70

90

100

010

515

20

EFFICIENCY vs. LED CURRENT

(vs. INDUCTANCE)

LED CURRENT (mA)

10

µH

4.7

µH

47

µH

22

µH

0

10

5

15

30

35

25

20

40

0

10152025

5

3035404550

INPUT RIPPLE vs. INDUCTANCE

INDUCTANCE (

µH)

0

1

2

4

5

3

6

0

2345

1

6

789

10

INPUT RIPPLE SPECTRUM

FREQUENCY (MHz)

0

5

10

20

15

25

0

20304050

10

60 70 80 90 100

LED CURRENT vs. DIRECT-PWM

DIMMING DUTY CYCLE

DIRECT-PWM DIMMING DUTY CYCLE (%)

200Hz < FREQ < 200kHz

Typical Operating Characteristics

Ω,

High-Efficiency, 26V Step-Up Converter

for White LED Main and Subdisplay Backlighting

4

_______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

-40°C to +85°C, unless otherwise noted.) (Notes 1, 3)

PARAMETER

CONDITIONS

MIN

MAX

UNITS

Maximum Duty Cycle

CTRL = V+, CS = GND

91

%

N-CHANNEL SWITCH

LX On-Resistance

2.25

Ω

LX Current Limit

Duty cycle = 90%

450

950

mA

guaranteed by design and characterization but are not production tested.

Note 2: The minimum output voltage is the input voltage minus the forward voltage drop of the Schottky diode:

Note 3: Specifications to -40°C are guaranteed by design and not production tested.