CAT3616

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9

Table 5. PIN DESCRIPTIONS

Pin #

Name

Function

1

MAIN1

MAIN1 LED cathode terminal (if not used, connect to VOUT) (Note 3)

2

ENM

Enable main LED (MAIN1 to MAIN4) input. Active low

3

ENS

Enable sub LED (SUB1, SUB2) input. Active low

4

EN

Device enable input. Active high.

5

VOUT

Charge pump output connected to the LED anodes

6

VIN

Supply voltage.

7, 8

C1−, C1+

Bucket capacitor 1 terminal

9, 10

C2−, C2+

Bucket capacitor 2 terminal

11

GND

Ground reference

12

SUB2

SUB2 LED cathode terminal (if not used, connect to VOUT) (Note 3)

13

SUB1

SUB1 LED cathode terminal (if not used, connect to VOUT) (Note 3)

14

MAIN4

MAIN4 LED cathode terminal (if not used, connect to VOUT) (Note 3)

15

MAIN3

MAIN3 LED cathode terminal (if not used, connect to VOUT) (Note 3)

16

MAIN2

MAIN2 LED cathode terminal (if not used, connect to VOUT) (Note 3)

TAB

TAB

Connect to Ground on PCB

3. MAIN1 to MAIN4, SUB1, SUB2 pins should not be left floating. They should be connected to the LED cathode, or tied to VOUT pin if not used.

Pin Function

VIN is the supply pin for the charge pump. A small 1

mF

ceramic bypass capacitor is required between the VIN pin

and ground near the device. The operating input voltage

range is up to 5.5 V. When the input supply falls below the

undervoltage threshold (2 V), all LED channels are disabled.

EN is the enable logic input. Logic level for high and low are

set at 1.3 V and 0.4 V respectively. When EN is initially

taken high, the device becomes enabled and all LED

currents remain at 0 mA. To place the device into zero

current shutdown mode, the EN pin must be held low for

1.5 ms or more.

ENM, ENS are the active low enable/ dimming control logic

inputs for respectively main and sub LED channels. The

falling edge of the first pulse applied to ENM and ENS sets

the current for respectively the main and sub LED channels

to their full scale of 31 mA. On each consecutive falling edge

of the pulse applied to ENM and ENS, the LED current is

is set to zero. The next pulse resets the current back to the full

scale of 31 mA.

VOUT is the charge pump output that is connected to the

LED anodes. A small 1

mF ceramic bypass capacitor is

required between the VOUT pin and ground near the device.

GND is the ground reference for the charge pump. The pin

must be connected to the ground plane on the PCB.

C1+, C1− are connected to each side of the 1

mF ceramic

bucket capacitor C1.

C2+, C2− are connected to each side of the 1

mF ceramic

bucket capacitor C2.

MAIN1−4, SUB1−2 provide the internal regulated current

for each of the LED cathodes. These pins enter a high

impedance zero current state whenever the device is placed

in shutdown mode. In applications using less than six LEDs,

the unused channels should be wired directly to VOUT. This

ensures the channel is automatically disabled dissipating

less than 200

mA.

TAB is the exposed pad underneath the package. For best

thermal performance, the tab should be soldered to the PCB

and connected to the ground plane.