R1218K(DFN(PLP)1820-6) is the limited product as of March 2020. R1218 Series Step-up DC/DC converter for White LED Backlight No. EA-166-180704 OUTLINE The R1218x Series are PWM control type step-up DC/DC converter ICs with low supply current. The R1218x is fully dedicated to drive White LED with constant current. Each of these ICs consists of an NMOS FET, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), an over-voltage protection circuit (OVP). The R1218x can drive white LEDs with high efficiency with low supply current. A diode is built-in the R1218xxx1A, therefore it is possible to drive up to 4LEDs without an external diode. The R1218xxx2A, an external diode is necessary, however, up to 7 serial LEDs can be driven with the R1218xxx2A. Constant current can be set with an external resistance value. Dimming control is possible by PWM signal for CE pin. Feedback voltage is 0.2V, therefore power loss by current setting resistor is small and efficiency is good. Maximum duty cycle is internally fixed, Typ. 91% to 92%. LEDs can be driven from low voltage. Protection circuits are the current limit of Lx peak current, the over voltage limit of output, and the under voltage lockout function. Packages are standard SOT-23-6 and very tiny DFN(PLP)1820-6. FEATURES Input voltage.................................................. 1.8V to 5.5V Built-in 400mA, 1.5, 20V Nch MOSFET and diode (R1218xxx1A) Built-in 400mA, 1.5, 33V Nch MOSFET (R1218xxx2A) Oscillator Frequency (PWM control) ............. 1.2MHz Maximum Duty Cycle .................................... Typ. 91% to 92% Feedback Voltage ......................................... Typ. 0.2V UVLO Threshold Voltage .............................. Typ. 1.6V (Hysteresis Typ. 0.1V) Lx Current limit Protection ............................. Typ. 700mA Over Voltage Protection (OVP) Threshold .... Typ. 9.5V (R1218x021A) Typ. 14.0V (R1218x031A) Typ. 18.5V (R1218x041A) Typ. 23.0V (R1218x052A) Typ. 27.5V (R1218x062A) Typ. 31.5V (R1218x072A) LED dimming control ..................................... by external PWM signal (Frequency 200Hz to 5kHz) to CE pin by feedback voltage and filtered PWM signal (high frequency) Packages ...................................................... DFN(PLP)1820-6, SOT-23-6 APPLICATIONS White LED Backlight for portable equipment 1 R1218K(DFN(PLP)1820-6) is the limited product as of March 2020. R1218x No. EA-166-180704 SELECTION GUIDE The OVP threshold, the built-in diode, and the package for the ICs can be selected at the users request. Selection Guide Product Name Package Quantity per Reel Pb Free Halogen Free R1218Kxxxx-TR DFN(PLP)1820-6 5,000 pcs Yes Yes R1218Nxxxx-TR-FE SOT-23-6 3,000 pcs Yes Yes xx xx: The combination of the OVP threshold and with/without of built-in diode can be designated. Code OVP Threshold Built-in Diode 021A 9.5 V Yes 031A 14.0 V Yes 041A 18.5 V Yes 052A 23.0 V No 062A 27.5 V No 072A 31.5 V No 2