R1223N SERIES PWM/VFM step-down DC/DC Controller NO.EA-065-181003 OUTLINE The R1223N Series are CMOS-based PWM step-down DC/DC Converter controllers with low supply current. Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip enable circuit, and resistors for voltage detection. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with only four external components, or a power-transistor, an inductor, a diode and a capacitor. With a PWM/VFM alternative circuit, when the load current is small, the operation is automatically switching into the VFM oscillator from PWM oscillator, therefore the efficiency at small load current is improved. The R1223NxxxB type, which is without a PWM/VFM alternative circuit, is also available. If the term of maximum duty cycle keeps on a certain time, the embedded protection circuit works. There are two types of protection function. One is latch-type protection circuit, and it works to latch an external Power MOSFET with keeping it disable. To release the condition of protection, after disable this IC with a chip enable circuit, enable it again, or restart this IC with power-on. The other is Reset-type protection circuit, and it works to restart the operation with soft-start and repeat this operation until maximum duty cycle condition is released. Either of these protection circuits can be designated by users request. FEATURES Input Voltage Range ....................................................2.3V to 13.2V Output Voltage Range..................................................1.5V to 5.0V (0.1V step) Output Voltage Accuracy..............................................2.0% Oscillator Frequency....................................................300kHz, 500kHz High Efficiency .............................................................Typ. 90% Standby Current ...........................................................Typ. 0A Temperature-Drift Coefficient of Output Voltage ..........Typ. 100ppm/C Built-in Soft-start Circuit Built-in Latch-type or Reset type Protection Circuit Package.......................................................................SOT-23-5 APPLICATION Power source for hand-held communication equipment, cameras, video instruments such as VCRs, camcorders. Power source for battery-powered equipment. Power source for household electrical appliances. 1 R1223N BLOCK DIAGRAM OSC VIN VOUT EXT Vref PWM/VFM Protection CONTROL Soft Start Chip Enable CE GND SELECTION GUIDE In the R1223N Series, the output voltage, the oscillator frequency, switching mode and type of short protection (Latch or Reset) for the IC are selectable at the users request. Product Name Package Quantity per Reel Pb Free Halogen Free R1223Nxx2 -TR-FE SOT-23-5 3,000pcs Yes Yes *1 xx : The output voltage can be designated in the range from 1.5V(15) to 5.0V(50) in 0.1V steps. : Designation of the oscillator frequency, switching mode and type of short protection. A) 300kHz, with a PWM/VFM alternative circuit, Latch-type protection B) 500 kHz, with a PWM/VFM alternative circuit, Latch-type protection C) 300kHz, without a PWM/VFM alternative circuit, Latch-type protection D) 500kHz, without a PWM/VFM alternative circuit, Latch-type protection E) 300kHz, with a PWM/VFM alternative circuit, Reset-type protection F) 500 kHz, with a PWM/VFM alternative circuit, Reset-type protection G) 300kHz, without a PWM/VFM alternative circuit, Reset-type protection H) 500kHz, without a PWM/VFM alternative circuit, Reset-type protection 2