ELP3321|High Performance, Constant Current Switching Regulator For 11PCS White LED In Series

ELP3321|High Performance, Constant Current Switching Regulator For 11PCS White LED In Series


High Performance, Constant Current Switching Regulator​​ 

For 11PCS White LED In Series






General Description​​ ​​ 

The​​ ELP3321 is a 1.0MHz PWM boost switching regulator designed for constant-current white LED driver applications. The​​ ELP3321 can drive a string of up to 11 white LEDs in series, ensuring uniform brightness and eliminating several ballast resistors. The​​ ELP3321 implements a constant frequency 1.0MHz PWM control scheme. The high frequency PWM operation also saves board space by reducing external component sizes. To improve efficiency, the feedback voltage is set to 200mV, which reduces the power dissipation in the current setting resistor. Highly integration and internal compensation network minimizes as 5 external component counts. Optimized operation frequency can meet the requirement of small LC filters value and low operation current with high efficiency.





  • WLED Backlight driver​​ ​​ 

  • OLED Backlight driver​​ ​​ 

  • PDA​​ ​​ 

  • MID



  • Up to 94% efficiency​​ 

  • Shut-down current:<1uA

  • Output voltage Up to 37V

  • Internal Compensation, Soft-start

  • Support down to 1% Dimming Duty Cycle

  • 1.0MHz fixed frequency switching

  • High switch on current:1.5A

  • Available in SOT23-6&TDFN-6(2mm×2mm) Package



​​ Typical Application Circuit















Ordering Information






















Marking​​ Information






















Functional Pin Description























Pin Description





















Function Block Diagram



























Absolute Maximum Ratings​​ Note 1


  • Input Voltage to GND ------------------------------------------------------------------- ----0.3V to 6.5V

  • ​​ LX /FB to GND --------------------------------------------------------------------------​​ ----0.3V to 46V​​ 

  • Other pin to GND ---------------------------------------------------------------------------​​ -0.3V to 6.5V​​ 

  • Operating Ambient Temperature Range (TA) ------------------------------------------- -40℃ to 85°C​​ 

  • Storage Temperature Range ------------------------------------------------------------- −65℃ to 165℃​​ 

  • Maximum Soldering Temperature (at leads, 10 sec) -------------------------------------------- 260°C


Note 1.​​ Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.





Thermal Information


  • Maximum Power Dissipation ( PD,TA=25°C) ------------------------------------------------- 0.5W

  • Thermal Resistance ---------------------------------------------------------------------------- 250℃/W​​ 

  • Maximum Power Dissipation (TDFN-6, PD,TA=25℃) --------------------------------------- 1.2W​​ 

  • Thermal Resistance (TDFN-6, JA) ------------------------------------------------------------ 95℃/W




ESD Susceptibility


  • HBM(Human Body Mode) ------------------------------------------------------------------------ 2KV​​ ​​ 

  • MM(Machine Mode) ------------------------------------------------------------------------------- 200V




Electrical Characteristics

(VIN=3.3V,​​ ​​ CIN=10uF,​​ ​​ COUT=2.2uF,​​ ​​ L=4.7uH)