MP3398D – 4-STRING, 350MA/STRING, STEP-UP, WHITE LED CONTROLLER

MP3398D Rev. 1.0

www.MonolithicPower.com

9

5/23/2016

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2016 MPS. All Rights Reserved.

PIN FUNCTIONS

SOIC16

Pin #

SOIC20

Pin #

Name

Description

1

1

COMP

Step-up converter compensation. COMP compensates for the regulation

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

2

2

EN

Enable control input. A voltage on EN greater than 1.4V turns the MP3398D

on; a voltage less than 0.6V turns the MP3398D off. Do not leave EN floating.

3

3

PWM

Input signal for PWM brightness control. By applying a PWM signal on

PWM, the LED current can be chopped, and the average current equals ISET x

determines the LED current dimming ratio. A lower dimming frequency can

result in a smaller dimming current. In general, 200Hz to 2kHz is suitable for

most LED current dimming applications. If PWM is floating, weakly pull it to

GND internally. If PWM dimming is not required, pull PWM to a high voltage

4

5

GND

Ground of the IC.

5

7

OSC

Switching frequency set. Connect a resistor between OSC and GND to set

the step-up converter switching frequency. The OSC voltage is regulated to

1.23V. The clock frequency is proportional to the current sourced from OSC.

6

8

ISET

LED current set. Tie a current-setting resistor from ISET to ground to program

the current in each LED string. The ISET voltage is regulated to 1.24V. The

LED current is proportional to the current through the ISET resistor.

7

9

ADIM

Signal input for analog brightness control. The LED current amplitude is

determined by ADIM, and the input signal is a PWM signal. An internal R-C filter

(10M

Ω resistor and 100pF capacitor) is integrated into ADIM. If a PWM signal is

applied to ADIM, a frequency greater than 20kHz is recommended to achieve

better PWM signal filtering and ensure that the amplitude voltage is higher than

1.4V and the low-level voltage is less than 0.6V. If ADIM is floating, weakly pull

it to GND internally. If analog dimming is not required, pull ADIM to a high

8

10

LED4

LED string 4 current input. LED4 is the open-drain output of an internal

dimming-control switch. Connect the LED string 4 cathode to LED4.

9

11

LED3

LED string 3 current input. LED3 is the open-drain output of an internal

dimming control switch. Connect the LED string 3 cathode to LED3.

10

12

LED2

LED string 2 current input. LED2 is the open-drain output of an internal

dimming control switch. Connect the LED string 2 cathode to LED2.

11

13

LED1

LED string 1 current input. LED1 is the open-drain output of an internal

dimming control switch. Connect the LED string 1 cathode to LED1.

12

14

OVP

Over-voltage protection input. Connect a resistor divider from the output to

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

MP3398D triggers over-voltage protection.