CAT3604 Datasheet, PDF (9/11 Pages) Catalyst Semiconductor – 4-Channel Regulated Charge Pump White LED Driver

TYPICAL CHARACTERISTICS
V_IN = 3.6V, EN = V_IN, C_IN = C_OUT = 1µF, unless otherwise specified.
Foldback Current Limiting
5
4
1x mode
3
2
1
0
0 100 200 300 400 500
OUTPUT CURRENT [mA]
CAT3604
RECOMMENDED LAYOUT
When the driver is in the 1.5x charge pump mode,
the 1MHz switching frequency operation requires
to minimize trace length and impedance to ground
on all 4 capacitors. A ground plane should cover the
area on the bottom side of the PCB opposite to the
IC and the bypass capacitors. Capacitors Cin and
Cout require short connection to ground which can
be done with multiple vias as shown on Figure 2. A
square copper area matches the QFN16 exposed
pad (GND) which is connected by a trace to the pin
12 pad (GND). A large via (metalized hole) centered
in the square pad provides a low impedance
connection to the ground plane on the opposite
side of the PCB and allows the heat dissipated by
the driver IC to spread out resulting in excellent
thermal performance.
0.65 mm
Figure 2: PCB Layout
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
2.25 mm
0.35 mm
Figure 3: Recommended QFN 16 Package Land Pattern
9
Doc. No. 5008, Rev. I