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MAX1582 Datasheet, PDF (4/10 Pages) Maxim Integrated Products – High-Efficiency, 26V Step-Up Converter for White LED Main and Subdisplay Backlighting
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High-Efficiency, 26V Step-Up Converter
for White LED Main and Subdisplay Backlighting
ELECTRICAL CHARACTERISTICS (continued)
(VV+ = +3.0V, VOUT1 = +20V, L1 = 22µH, COUT = 0.1µF, CCOMP = 0.022µF, RSENSE = 7.5Ω, VCTRL = +1.5V, EN1 = EN2 = V+, TA =
-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
Note 1: Limits are 100% production tested at TA = +25°C for UCSP parts. Limits over the entire operating temperature range are
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:
VOUT(MIN) = VV+ - VDIODE
Note 3: Specifications to -40°C are guaranteed by design and not production tested.
Typical Operating Characteristics
(See the Typical Applications Circuit, VV+ = VVP = 3.6V, ILED = 15mA, L1 = 22µH, COUT1 = 0.1µF, CCOMP = 0.022µF, RSENSE = 7.5Ω,
VCTRL = 1.5V, 4 LEDs, TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. LED CURRENT
(vs. NUMBER of LEDs)
100
90
6 LEDs
80
70
4 LEDs
60
2 LEDs
50
40
0
5
10
15
20
LED CURRENT (mA)
INPUT RIPPLE vs. INDUCTANCE
40
35
30
25
20
15
10
5
0
0 5 10 15 20 25 30 35 40 45 50
INDUCTANCE (µH)
EFFICIENCY vs. LED CURRENT
(vs. INPUT VOLTAGE)
100
90
2.7 VIN
80
70
3.6 VIN
60
4.2 VIN
50
40
0
5
10
15
20
LED CURRENT (mA)
INPUT RIPPLE SPECTRUM
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8 9 10
FREQUENCY (MHz)
EFFICIENCY vs. LED CURRENT
(vs. INDUCTANCE)
100
90
22µH
10µH
80
70
47µH
4.7µH
60
50
40
0
5
10
15
20
LED CURRENT (mA)
LED CURRENT vs. DIRECT-PWM
DIMMING DUTY CYCLE
25
20
15
10
5
VCTRL = SQUARE WAVE
200Hz < FREQ < 200kHz
0
0 10 20 30 40 50 60 70 80 90 100
DIRECT-PWM DIMMING DUTY CYCLE (%)
4 _______________________________________________________________________________________
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