MAX158 Maxim, MAX158 Datasheet - Page 4

• Manufacturer Part Number: MAX158
• Description: High-Efficiency / 26V Step-Up Converter for White LED Main and Subdisplay Backlighting
• Manufacturer: Maxim

High-Efficiency, 26V Step-Up Converter
for White LED Main and Subdisplay Backlighting
ELECTRICAL CHARACTERISTICS (continued)
(V
-40°C to +85°C, unless otherwise noted.) (Notes 1, 3)
Note 1: Limits are 100% production tested at T
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.
(See the Typical Applications Circuit, V
V
4
Maximum Duty Cycle
N-CHANNEL SWITCH
LX On-Resistance
LX Current Limit
CTRL
V+
100
_______________________________________________________________________________________
90
80
70
60
50
40
40
35
30
25
20
15
10
= +3.0V, V
5
0
= 1.5V, 4 LEDs, T
0
0
guaranteed by design and characterization but are not production tested.
PARAMETER
5
INPUT RIPPLE vs. INDUCTANCE
6 LEDs
EFFICIENCY vs. LED CURRENT
10 15 20 25
(vs. NUMBER of LEDs)
5
OUT1
LED CURRENT (mA)
INDUCTANCE (µH)
= +20V, L1 = 22µH, C
2 LEDs
10
A
4 LEDs
= +25°C, unless otherwise noted.)
30 35 40 45 50
15
CTRL = V+, CS = GND
Duty cycle = 90%
V+
20
= V
OUT
VP
A
= 3.6V, I
= 0.1µF, C
= +25°C for UCSP parts. Limits over the entire operating temperature range are
100
90
80
70
60
50
40
6
5
4
3
2
1
0
0
0
V
OUT(MIN)
1
LED
EFFICIENCY vs. LED CURRENT
2.7 V
CONDITIONS
INPUT RIPPLE SPECTRUM
COMP
2
= 15mA, L1 = 22µH, C
(vs. INPUT VOLTAGE)
IN
5
3
LED CURRENT (mA)
FREQUENCY (MHz)
= V
= 0.022µF, R
4
4.2 V
V+
10
5
IN
- V
Typical Operating Characteristics
3.6 V
6
DIODE
IN
7
15
SENSE
8
9
OUT1
20
= 7.5Ω, V
10
= 0.1µF, C
100
90
80
70
60
50
40
25
20
15
10
CTRL
5
0
0
MIN
450
0
91
COMP
= +1.5V, EN1 = EN2 = V+, T
10
DIRECT-PWM DIMMING DUTY CYCLE (%)
10µH
LED CURRENT vs. DIRECT-PWM
EFFICIENCY vs. LED CURRENT
20 30 40 50
DIMMING DUTY CYCLE
5
= 0.022µF, R
(vs. INDUCTANCE)
LED CURRENT (mA)
22µH
47µH
10
V
200Hz < FREQ < 200kHz
CTRL
MAX
2.25
950
60 70 80 90 100
= SQUARE WAVE
SENSE
15
4.7µH
UNITS
= 7.5Ω,
mA
%
Ω
20
A
=