SP7618ER-LSLASHTR datasheet(8/10 Pages) SIPEX

8 / 10 page

Date: Dec 5-06 Rev E

Constant Current LED Driver

To obtain the best performance from the

SP768, a printed circuit board with ground

plane is required. High quality, low series

resistance ceramic µF bypass capacitors

should be used at the Vcc pin (pin 3). These

capacitors must be located as close to pins

3 – 6 as possible. The traces connecting the

pins and the bypassing capacitors must be

kept short and should be made as wide as

possible. Pins – 2 are connected together

internally but we recommend connecting the

LED cathode to both pins to avoid additional

power losses at high current. Pins 6, 7 and

8 should be connected to the ground plane.

BoardlayoutshouldpreventhighLEDground

current from flowing through signal ground

connected to pin 6. This pin is a separate

ground for the reference and logic sections

of the SP768. The quiescent current for the

partflowsintotheVCCpinandoutoftheGND

pin. This current is proportional to the Iled

current divided by approximately 500.

TIMING DIAGRAM

BOARD LAYOUT AND GROUNDING

SP7618ER-L/TR Datasheet(PDF) 8 Page - Sipex Corporation