TM
MP1518 – FIXED FREQUENCY WHITE LED DRIVER
ELECTRICAL CHARACTERISTICS
(continued)
V
IN
= V
EN
= 5V, T
A
= +25°C, unless otherwise noted.
Parameters
Enable
EN Threshold
EN Threshold
EN Hysteresis
EN Input Bias Current
Feedback
FB Voltage
FB Input Bias Current
Output Switch
SW On-Resistance
(4)
SW Current Limit
(4)
Thermal Shutdown
(4)
Symbol
Condition
V
EN
Rising
V
EN
Rising, V
IN
= 2.5V
V
EN
= 0V, 5V
Min
1.0
0.8
Typ
1.35
90
Max
1.6
Units
V
V
mV
µA
mV
nA
Ω
mA
°C
1
94
-600
104
-300
0.5
350
160
114
V
FB
= 0.1V
R
ON
Duty Cycle = 60%
Notes:
4) Guaranteed by design.
PIN FUNCTIONS
TSOT23-6
Pin #
1
2
3
QFN8
Pin #
8
1, 5
6
Name Pin Function
SW
GND
FB
Power Switch Output. SW is the drain of the internal MOSFET switch. Connect
the power inductor and output rectifier to SW. SW can swing between GND and
25V.
Ground.
Feedback Input. The MP1518 regulates the voltage across the current sense
resistor between FB and GND. Connect a current sense resistor from the bottom
of the LED string to GND. Connect the bottom of the LED string to FB. The
regulation voltage is 104mV.
Regulator On/Off Control Input. A high input at EN turns on the converter, and a
low input turns it off. When not used, connect EN to the input source for
automatic startup.
The EN pin cannot be left floating.
Over Voltage Input. OV measures the output voltage for open circuit protection.
Connect OV to the output at the top of the LED string.
Input Supply Pin. Must be locally bypassed.
4
5
6
4
3
2
EN
OV
IN
MP1518 Rev. 1.6
7/25/2006
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3
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