RP509x Series 0.5A/1A PWM/VFM Step-down DC/DC Converter with Synchronous Rectifier No. EA-362-210827 OUTLINE The RP509x is a low supply current PWM/VFM step-down DC/DC converter with synchronous rectifier (1) featuring 0.5 A/1 A output current . Internally, a single converter consists of a reference voltage unit, an error amplifier, a switching control circuit, a mode control circuit, a soft-start circuit, an undervoltage lockout (UVLO) circuit, a thermal shutdown circuit, and switching transistors. The RP509x is employing synchronous rectification for improving the efficiency of rectification by replacing diodes with built-in switching transistors. Using synchronous rectification not only increases circuit performance but also allows a design to reduce parts count. Output voltage controlling method is selectable between a PWM/VFM auto-switching control type and a forced PWM control type, which further reduces noise than a normal PWM control under a light load, and these types can be set by the MODE pin. Output voltage type is selectable between an internally fixed output voltage type and an externally adjustable output voltage type. Protection circuits in the RP509x is current limit circuit and thermal shutdown circuit. LX current limit value (Typ.) is selectable between 1.6 A and 1.0 A. The RP509Z is available in WLCSP-6-P6 which achieves high-density mounting on boards. Using capacitor of 0402-/1005-size (inch/mm) and inductor of 0603-/1608-size (inch/mm) as external parts help to save space for devices. The RP509N is available in SOT-23-6. FEATURES Input Voltage Range (Maximum Rating) 2.3 V to 5.5 V (6.5 V) Output Voltage Range (Fixed Output Voltage Type) 0.6 V to 3.3 V, settable in 0.1 V steps (Adjustable Output Voltage Type) 0.6 V to 5.5 V (2) Output Voltage Accuracy (Fixed Output Voltage Type) 1.5% (VSET 1.2 V), 18 mV (VSET < 1.2 V) Feedback Voltage Accuracy (Adjustable Output Voltage Type) 9 mV (VFB = 0.6 V) Output Voltage/Feedback Voltage Temperature Coefficient 100 ppm/C Selectable Oscillator Frequency Typ. 6.0 MHz Oscillator Maximum Duty Min. 100% Built-in Driver ON Resistance (VIN = 3.6 V) Typ. Pch. 0.175 , Nch. 0.155 (RP509Z) Typ. Pch. 0.195 , Nch. 0.175 (RP509N) Standby Current Typ. 0 A UVLO Detector Threshold Typ. 2.0 V Soft-start Time Typ. 0.15 ms Inductor Current Limit Circuit Typ. 1.6 A/1.0 A, selectable Current Limit Package WLCSP-6-P6 ( 1.28 mm x 0.88 mm x 0.64 mm ) SOT-23-6 ( 2.9 mm x 2.8 mm x 1.1 mm ) (1) This is an approximate value. The output current is dependent on conditions and external components. (2) VSET = Set Output Voltage 1 RP509x No. EA-362-210827 APPLICATIONS Portable Communication Equipment: Mobiles/Smartphones, Digital Cameras and Note-PCs Li-ion Battery-used Equipment SELECTION GUIDE (1) The set output voltage, the output voltage type, the auto-discharge function , and the LX current limit for the ICs are user-selectable options. Selection Guide Product Name Package Quantity per Reel Pb Free Halogen Free RP509ZxxX -E2-F WLCSP-6-P6 5,000 pcs Yes Yes RP509NxxX -TR-FE SOT-23-6 3,000 pcs Yes Yes xx: Specify the set output voltage (VSET) Fixed Output Voltage Type: 06 to 33 (0.6 V to 3.3 V, 0.1 V steps) The voltage in 0.05 V step is shown as follows. 1.05 V: RP509Z101B5 1.15 V: RP509N111x5 Adjustable Output Voltage Type: 00 only X: Specify the LX Current Limit (ILXLIM) Typ. 1.6 A: 1 Typ. 1.0 A: 2 : Specify the version Version Output Voltage Type Auto-discharge Oscillator Frequency V SET A No Fixed 0.6 V to 3.3 V B Yes 6.0 MHz C No Adjustable 0.6 V to 5.5 V D Yes (1) Auto-discharge function quickly lowers the output voltage to 0 V, when the chip enable signal is switched from the active mode to the standby mode, by releasing the electrical charge accumulated in the external capacitor. 2