CAT3606 Datasheet, PDF (9/11 Pages) Catalyst Semiconductor – 6-Channel Low Noise Charge Pump White LED Driver

CAT3606
TYPICAL CHARACTERISTICS
(V_IN = 3.6 V, EN = V_IN, ENM = ENS = GND, C_IN = C_OUT = 1 mF, T_AMB = 25°C, unless otherwise specified.)
5
1.24
4
1.22
1x Mode
3
1.20
2
1.18
1
0
0
100
200
300
400
500
OUTPUT CURRENT (mA)
Figure 21. Foldback Current Limiting
1.16
−50 −25
0
25
50 75 100 125
TEMPERATURE (°C)
Figure 22. RSET Pin Voltage vs. Temperature
ENM & ENS
5V/div
VOUT
1V/div
Tot. LED
Current
50mA/div
200 msec/div
Figure 23. PWM Dimming at 1 kHz on ENM and ENS
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 24.
A square copper area matches the QFN16 exposed pad
(GND) and must be connected to the ground plane
underneath. The use of multiple via will improve the heat
dissipation.
Figure 24. PCB Layout
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