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

CAT3604
TYPICAL CHARACTERISTICS
(V_IN = 3.6 V, EN = V_IN, C_IN = C_OUT = 1 mF, unless otherwise specified.)
5
4
1x Mode
3
2
1
0
0
100
200
300
400
500
OUTPUT CURRENT (mA)
Figure 21. Foldback Current Limiting
Recommended Layout
When the driver is in the 1.5x charge pump mode, the
1 MHz 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 22.
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 22. PCB Layout
2.25 mm
0.35 mm
Figure 23. Recommended QFN 16
Package Land Pattern
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