Overview
The IS31LT3350 is a continuous mode inductive
step-down converter, designed for driving a single LED or
multiple series connected LEDs efficiently from a voltage
source higher than the LED voltage. The chip operates
from an input supply between 6V and 40V and provides
an externally adjustable output current of up to 750mA.
Depending upon supply voltage and external
components, this can provide up to 30 watts of output
power.
The IS31LT3350 includes an integrated output switch
and a high-side output current sensing circuit, which uses
an external resistor to set the nominal average output
current.
Output current can be adjusted linearly by applying an
external control signal to the ADJ pin. The ADJ pin will
accept either a DC voltage or a PWM waveform. This will
provide either a continuous or a gated output current.
Applying a voltage of 0.2V or lower to the ADJ pin turns
the output off and switches the chip into a low current
standby state.
The chip is assembled in SOT23-5 and SOT89-5
package. SOT23-5 is available for 350mA output current
application. SOT89-5 is available for 750mA output
current application.