CAT4238TD-GT3

The CAT4238 is a DC/DC step−up converter that delivers an
accurate constant current ideal for driving LEDs. Operation at a fixed
switching frequency of 1 MHz allows the device to be used with small
value external ceramic capacitors and inductor. LEDs connected in
series are driven with a regulated current set by the external resistor
R1. LED currents up to 40 mA can be supported over a wide range of
input supply voltages up to 5.5 V, making the device ideal for battery
−powered applications. The CAT4238 high−voltage output stage is
perfect for driving mid−size and large panel displays containing up to
ten white LEDs in series.
LED dimming can be done by using a DC voltage, a logic signal, or
a pulse width modulation (PWM) signal. The shutdown input pin
allows the device to be placed in power−down mode with “zero”
quiescent current.
In addition to thermal protection and overload current limiting, the
device also enters a very low power operating mode during “Open
LED” fault conditions. The device is housed in a low profile (1 mm
max height) 5−lead thin SOT23 package for space critical
applications.