CAT4134

© Catalyst Semiconductor, Inc.

7

Doc. No. MD-5021 Rev. B

Characteristics subject to change without notice.

PIN DESCRIPTION

Pin #

Name

Function

1

FLASH

Logic input, set high to select the flash mode.

2

EN

Enable control logic input (Active High).

3

PGND

Power ground reference.

4

AGND

Analog ground reference.

5

LED2

LED channel 2, connected to the LED cathode.*

6

LED1

LED channel 1, connected to the LED cathode.*

7

RFLASH

Resistor connection to set Flash mode LED current.

8

RSET

Resistor connection to set Movie mode LED current.

9

VIN

Power supply input.

10,11

SW

Drain connection of low resistance power MOSFET.

12

OVP

Over Voltage Protection comparator input

* LED1 or LED2 pin should not be left floating.

PIN FUNCTION

VIN is the supply voltage input. The device is

compatible with supply voltages down to 2.8V and up to

4.2V. Internal under-voltage lockout (UVLO) circuitry

will automatically prevent the device from operating

whenever the supply falls below 1.9V. For operation up

to maximum rated loads a bypass ceramic capacitor of

10µF is recommended between the VIN and GND pins

near the device.

EN is the enable logic input (active high). When the pin

voltage is taken below 0.4V, the device enters

shutdown mode, drawing nearly zero current. At pin

voltages greater than 1.4V, the device is fully enabled.

FLASH is the logic input (active high) used to control

Flash mode operation. When the pin voltage is taken

above 1.4V, the device transitions from Movie mode to

Flash mode. When the pin voltage is taken back below

0.4V, the device returns back to Movie mode operation.

RSET, RFLASH pins allow to set the LED current

respectively in Movie and Flash mode. These pins,

regulated at 1.2V, must be connected to a pull-down

resistor tied to ground. The LED current is a function of

the resistor value.

GND is the ground reference for the driver. The pin

must be connected to the ground plane on the PCB.

SW pin is the drain terminal of the internal low

resistance power switch. The inductor and the Schottky

diode anode should be connected to the SW pin.

Traces going to the SW pin should be as short as

possible with minimum loop area. This pin contains

over-voltage circuitry which becomes active above 18V.

In the event of an “open-LED” fault condition, the

device will enter a low power mode and the SW pin will

be clamped to approximately 21V.

LED1, LED2 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 with only one

string of LEDs, the two LED pins should be tied

together. LED pins should not be left floating.

OVP is the overvoltage protection input pin. When the

pin voltage exceeds the 1.2V overvoltage threshold

then drops down. As soon as the OVP pin voltage falls

again.

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.