MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER

MP3394S Rev. 1.03

www.MonolithicPower.com

6

3/21/2013

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PIN FUNCTIONS

TSSOP16EP

&SOIC16

Pin #

SOIC20

Pin #

Name

Description

1

1

COMP

Step-up Converter Compensation Pin. This pin compensates the regulation

control loop. Connect a ceramic capacitor from COMP to GND.

2

2

EN

Enable Control Input. A voltage greater than 1.8V will turn the part on and

less than 0.6 V will turn the part off. Do not let this pin float.

3

3

DBRT

Brightness Control Input. Apply a PWM signal on this pin for for external

PWM dimming mode. Apply a DC voltage range from 0.2V to 1.2V on this

pin to linearly set the internal dimming duty cycle from 0% to 100% for DC-

input PWM dimming mode. The MP3394S has positive dimming polarity on

DBRT.

4

5

GND

Ground.

5

7

OSC

Switching Frequency Set. Connect a resistor between OSC and GND to set

the step-up converter’s switching frequency. The voltage at this pin is

regulated to 1.22V. The clock frequency is proportional to the current

sourced from this pin.

6

8

ISET

LED Current Set. Tie a current-setting resistor from this pin to ground to

program the current in each LED string. This pin voltage is regulated to

1.22V. The LED current is proportional to the current through the ISET

resistor.

7

9

BOSC

Dimming Repetition Set. This is the timing pin for the oscillator to set the

dimming frequency. To use DC input PWM dimming mode, connect a

capacitor from this pin to GND to set the internal dimming frequency. A

saw-tooth waveform is generated on this pin. To use external PWM

dimming mode, connect a resistor from this pin to GND, and apply the

PWM signal on DBRT pin.

8

10

LED4

LED String 4 Current Input. This pin is the open-drain output of an internal

dimming control switch. Connect the LED String 4 cathode to this pin.

9

11

LED3

LED String 3 Current Input. This pin is the open-drain output of an internal

dimming control switch. Connect the LED String 3 cathode to this pin.

10

12

LED2

LED String 2 Current Input. This pin is the open-drain output of an internal

dimming control switch. Connect the LED String 2 cathode to this pin.

11

13

LED1

LED String 1 Current Input. This pin is the open-drain output of an internal

dimming control switch. Connect the LED String 1 cathode to this pin.

12

14

OVP

Over-Voltage Protection Input. Connect a resistor divider from output to this

pin to program the OVP threshold. When this pin voltage reaches 1.23V,

the MP3394S triggers Over Voltage Protection mode.

13

17

ISENSE

Current Sense Input. During normal operation, this pin senses the voltage

current–mode control and also to limit the inductor current during every

switching cycle. If this pin is not used for cascading applications, tie this pin

to GND; do not let this pin float.

14

18

GATE

Step-up Converter Power Switch’s Gate Driver Output. This pin drives the

external power N-MOS device.