AME5142 pdf datasheet (High Ef

The AME5142/5142A is a Boost DC/DC converter specifically
designed to drive white LEDs with a constant
current. The device can drive 1 to 6 LEDs in series or
multiple strings from a Li-lon cell. Series connection of
the LEDs provides identical LED currents resulting in uniform
brightness and eliminating the need for ballast resistors.
The AME5142/5142A switches at 1.2MHz, allowing
the use of tiny external components. The input
and output capacitor can be as small as 1mF(or 4.7mF),
saving space and cost versus alternative solutions. A low
feedback voltage minimizes power loss in the current
setting resistor for better efficiency. The AME5142/5142A
is available in SOT-26/TSOT-26 & SOT-25/TSOT-25 packages. The only difference between AME5142 and AME5142A
is feedback trip point. The AME5142 is 0.15V and
AME5142A is 0.104V.