SC440A

9

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Pin Descriptions

Pin #

Pin Name

Pin Function

1

IO1

Provides constant sink current to LED string 1.

2

AGND

Analog ground

3

FFLAG

Power failure signal output with open collector.

4

EN

Enable the device including requlator and LED drivers.

5

SS

Soft-start pin

6

OVPRTN

Over-voltage return

7

OVPIN

Over-voltage input

8, 12

PGND

Power ground

9, 10

SW

Collector of the internal power transistor – connect to the boost inductor and the rectifying diode.

11

N/C

Left open.

13

VIN

Input power supply.

14

IOSET

Current source IO value set pin – by selecting the resistor connected from this pin to GND, the

corresponding maximum current on all 6 strings are set.

15

SCP_EN

LED short-circuit protection pin – leaving this pin open enables the function, tying it to ground

disables it. If any IO pin connects to VIN, SCP_EN needs to be left open to activate the protection.

16

COMP

The output of the internal transconductance error amplifier – this pin is used for loop compensation.

17

VOUT

Output voltage pin – internal over-voltage Connect the output capacitor and the anode of

control pin for LED backlight strings.

18

PWM

PWM control pin for LED backlight strings.

19

IO6

Provides constant sink current to LED string 6.

20

IO5

Provides constant sink current to LED string 5.

21

IO4

Provides constant sink current to LED string 4.

22

IOGND

Constant sink current ground, tying to AGND.

23

IO3

Provides constant sink current to LED string 3.

24

IO2

Provides constant sink current to LED string 2.

T

Thermal Pad

Thermal pad for heatsinking purposes — connect — not connected internally

EN

STATUS

0

backlight disable

1

backlight enable

Note: When EN = 0; the boost is turned OFF and disabled.

Table 1.

Note: Any unused IO pin should be pulled up to VIN with the SCP_EN left open.