MP3394S—4-STRING, MAX 200mA/STRING WHITE LED DRIVER
MP3394S Rev. 1.03 www.MonolithicPower.com 6
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© 2013 MPS. All Rights Reserved.
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
across the external-inductor current-sensing resistor (R
SENSE
) for peak-
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.
