RP508K181B-EV 600 mA 6 MHz Synchronous Step-down DC/DC Converter Evaluation Board NO. EEV-318-K181B-190222 RP508K181B-EV is the evaluation board for RP508 which has the below features, benefits and specifications. OUTLINE The RP508K is a low supply current PWM/VFM step-down DC/DC converter with synchronous rectifier (1) featuring 600 mA output current. Internally, a single converter consists of an oscillator, a reference voltage unit, an error amplifier, a switching control circuit, a mode control circuit, a soft-start circuit, an under-voltage lockout (UVLO) circuit, an over current protection circuit, a thermal shutdown circuit and switching transistors. By the adoption of the synchronous rectification circuit with built-in switching transistors, the RP508K works as efficient step-down DC/DC converter, without connecting external diodes. Using synchronous rectification not only increases circuit performance but also allows a design to reduce parts count. Power controlling method can be selected from forced PWM control type or PWM/VFM auto switching control type by inputting a signal to the MODE pin. In low output current, forced PWM control switches at fixed frequency rate in order to reduce noise. Likewise, in low output current, PWM/VFM auto switching control automatically switches from PWM mode to VFM mode in order to achieve high efficiency. Output voltage is internally fixed type which allows output voltages that range from 0.8 V to 3.3 V in 0.1 V step. The output voltage accuracy is as high as 1.5% or 18 mV. Protection circuits included in the RP508K are over current protection circuit and thermal shutdown circuit. Over current protection circuit supervises the inductor peak current in each switching cycle, and if the current exceeds the L current limit (I ), it turns off P-channel Tr. Thermal shutdown circuit detects overheating of X LXLIM the converter if the output pin is shorted to the ground pin (GND) etc. and stops the converter operation to protect it from damage if the junction temperature exceeds the specified temperature. FEATURES Input Voltage Range (V ) 2.3 V to 5.5 V (Absolute Maximum Ratings: 6.5 V) IN Output Voltage Range (V ) 0.8 V to 3.3 V (Adjustable in 0.1 V steps) OUT Supply Current (I ) Typ. 15 A (VFM Mode with No-load) DD2 Standby Current (Istandby) Typ. 0 A Output Voltage Temperature Coefficient (V /Ta) Typ. 100 ppm/C OUT Oscillator Frequency (fosc) Typ. 6.0 MHz Maximum Duty Cycle (Maxduty) 100% Built-in Driver ON Resistance (R , R ) Typ. Pch. 0.33 , Nch. 0.24 (V = 3.6 V) ONP ONN IN UVLO Detector Threshold (V ) Typ. 2.0 V UVLO01 (1) This is an approximate value. The output current is dependent on conditions and external components. 1 RP508K NO. EEV-318-K181B-190222 Soft-start Time (tstart) Typ. 90 s LX Current Limit Circuit (ILXLIM) Typ. 1.1 A Output Voltage Accuracy 1.5% (VOUT 1.2 V) or 18 mV (VOUT < 1.2 V) Package DFN(PLP)1212-6F For more details on RP508 IC, please refer to