LT1942 datasheet(13/16 Pages) LINER

13 / 16 page

LT1942

1942fb

Layout Hints

Proper layout techniques must be followed to achieve

advertised performance of the part. Keep all SW and FB

traces short and small. There are several power ground

pins on the LT1942 and it is important to implement the

grounding properly. PGND14 is the power ground pin for

the AVDD and LED switchers. The output capacitor for both

the AVDD and LED switcher must be returned back to this

pin before being allowed to mix into the ground plane.

Similarly, PGND23 is the power ground pin for the VON and

VOFF switcher. Again, both output capacitors for the VON

and VOFF switchers need to return to the PGND23 pin

before mixing with the ground plane. Place the input

decoupling capacitor, which ties from the VCC pin to GND,

as close to the part as possible. Please refer to Figure 3 for

a recommended layout of the power path components.

The component names are those shown in the circuit of

Figure 4.

APPLICATIO S I FOR ATIO

VIN

LED1 STRING

LED2 STRING

LED OUTPUT

1942 F03

VON OUTPUT

GND

PLANE

LT1942

VOFF OUTPUT

AVDD OUTPUT

Figure 3: Power Path Component Recommended Layout

(Refer to Figure 4 Component Names)

LT1942 Datasheet(PDF) 13 Page - Linear Technology