TM
MP1518 – FIXED FREQUENCY WHITE LED DRIVER
ELECTRICAL CHARACTERISTICS (continued)
VIN = VEN = 5V, TA = +25°C, unless otherwise noted.
Parameters
Symbol
Condition
Min
Typ Max Units
Enable
EN Threshold
VEN Rising
1.0
0.8
1.35
90
1.6
V
V
EN Threshold
VEN Rising, VIN = 2.5V
EN Hysteresis
mV
µA
EN Input Bias Current
Feedback
VEN = 0V, 5V
VFB = 0.1V
1
FB Voltage
94
104
114
mV
nA
FB Input Bias Current
Output Switch
SW On-Resistance (4)
SW Current Limit (4)
Thermal Shutdown (4)
-600 -300
RON
0.5
350
160
Ω
Duty Cycle = 60%
mA
°C
Notes:
4) Guaranteed by design.
PIN FUNCTIONS
TSOT23-6 QFN8
Name Pin Function
Pin #
Pin #
Power Switch Output. SW is the drain of the internal MOSFET switch. Connect
1
2
8
SW the power inductor and output rectifier to SW. SW can swing between GND and
25V.
1, 5
GND 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.
3
4
6
4
FB
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
EN
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.
5
6
3
2
OV
IN
Input Supply Pin. Must be locally bypassed.
MP1518 Rev. 1.6
7/25/2006
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3
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