MAX1579 Maxim Integrated Products, MAX1579 Datasheet - Page 4

• Manufacturer Part Number: MAX1579
• Description: Complete Bias and White LED Power Supplies for Small TFT Displays
• Manufacturer: Maxim Integrated Products

Complete Bias and White LED Power Supplies
for Small TFT Displays
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 3, V
(Circuit of Figure 3, V
4
Note 1: All devices are 100% production tested at T
Note 2: V
Note 3: Time from CTRL going below the Dual-Mode threshold to IC shutdown.
N-CHANNEL SWITCH
LX On-Resistance
LX Leakage Current
LX Current Limit
_______________________________________________________________________________________
D1
PARAMETER
is the forward-voltage drop of diode D1 in Figure 3.
90
85
80
75
70
65
60
55
50
30
25
20
15
10
5
0
IN
-40
IN
0
= 3V, CTRL = ONBIAS = IN, T
= 3.6V, I
LED CURRENT vs. TEMPERATURE
-15
LED EFFICIENCY vs. I
5
6 LEDs
R
MAX1579
2 LEDs
LED CURRENT (mA)
R
TEMPERATURE (°C)
LED
CS
MAX1578
CS
= 13Ω
10
10
= 22Ω
= 20mA, 4 LEDs, CTRL = IN, T
I
V
Duty cycle = 90%
4 LEDs
LX
LX
= 190mA
= 28V, CTRL = GND
15
35
LED
8 LEDs
20
60
A
A
= +25°C. Limits over the operating temperature range are guaranteed by design.
= -40°C to +85°C, typical values are at T
25
85
CONDITIONS
A
= +25°C, unless otherwise noted.)
Typical Operating Characteristics
90
85
80
75
70
65
60
55
50
25
20
15
10
T
T
5
0
A
A
2.5
0
= +25°C
= +85°C
3.0
0.5
LED EFFICIENCY vs. V
LED CURRENT vs. V
I
LED
INPUT VOLTAGE (V)
3.5
A
CTRL VOLTAGE (V)
= 10mA
= +25°C, unless otherwise noted. Note 1)
1.0
MIN
4.0
500
I
LED
1.5
4.5
= 20mA
I
LED
CTRL
TYP
0.82
0.01
= 2mA
IN
700
2.0
1
5.0
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5.5
2.5
MAX
900
1.5
5
UNITS
mA
µA
Ω