A8430
White LED Driver Constant Current Step-up Converter
The A8430 is a noninverting boost converter that steps-up the input
voltage, to provide a programmable constant current output at up to
36 V for driving white LEDs in series. Driving LEDs in series ensures
A8430 MLPD
identical currents and uniform brightness. Up to four white LEDs can
be driven at 20 mA from a single cell Li-ion or a multicell NiMH power
source. Up to seven white LEDs can be driven by increasing the supply
voltage up to 10 V.
The A8430 incorporates a power switch and feedback sense amplifier
to provide a solution with minimum external components. The output
current can be set by adjusting a single external sense resistor and can
Approximate actual size
be varied with a voltage or filtered PWM signal when dimming control
is required. The high switching frequency of 1.2 MHz allows the use of
small inductor and capacitor values.
The A8430 is provided in a 5-pin 3 mm x 3 mm MLP package (part
number suffix EK), that has a nominal height of only 0.75 mm. The
lead-free version (part number suffix EK-T) has 100% lead-free matte
tin leadframe plating.
VIN
EN
1
2
3
5
4
SW
GND
FB
FEATURES
Same pad footprint as SOT-23-5
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Output voltage up to 36 V
R
θJA = 50 °C/W, see note 1, page 2
2.5 V to 10 V input
Drives up to 4 LEDs at 20 mA from a 2.5 V supply
Drives up to 5 LEDs at 20 mA from a 3 V supply
1.2 MHz switching frequency
300 mA switch current limit
1 µA shutdown current
ABSOLUTE MAXIMUM RATINGS
SW Pin ................................................–0.3 V to 36 V
Remaining Pins.................................. –0.3 V to 10 V
Ambient Operating Temperature, TA....... –40°C to 85°C
Junction Temperature, TJ(max)...............................150°C
Storage Temperature, TS .................... –55°C to 150°C
APPLICATIONS
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LED backlights
Portable battery-powered equipment
Cellular phones
PDAs (Personal Digital Assistant)
Camcorders, personal stereos, MP3 players, cameras
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Mobile GPS systems
Use the following complete part number when ordering:
Part Number
A8430EEK
Package
Description
Surface Mount
5-pin, MLPD
5-pin, MLPD
A8430EEK-T
Lead-Free, Surface Mount