XC9235/XC9236/XC9237 Series ETR0514-016 600mA Driver Tr. Built-In, Synchronous Step-Down DC/DC Converters GreenOperation Compatible GENERAL DESCRIPTION T he XC9235/XC9236/XC9237 series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42 P- channel MOS driver transistor and 0.52 N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. Operating voltage range is from 2.0V to 6.0V (A~C types), 1.8V to 6.0V (D~G types). For the D/F types which have a reference voltage of 0.8V (accuracy:2.0%), the output voltage can be set from 0.9V by using two external resistors. The A/B/C/E/G types have a fixed output voltage from 0.8V to 4.0V in increments of 0.05V (accuracy:2.0%). The device provides a high efficiency, stable power supply with an output current of 600mA to be configured using only a coil and two capacitors connected externally. With the built-in oscillator, either 1.2MHz or 3.0MHz can be selected for suiting to your particular application. As for operation mode, the XC9235 series is PWM control, the XC9236 series is automatic PWM/PFM switching control and the XC9237 series can be manually switched between the PWM control mode and the automatic PWM/PFM switching control mode, allowing fast response, low ripple and high efficiency over the full range of loads (from light load to heavy load). The soft start and current control functions are internally optimized. During stand-by, all circuits are shutdown to reduce current consumption to as low as 1.0A or less. The B/F/G types have a high speed soft-start as fast as 0.25ms in typical for quick turn- on. With the built-in UVLO function, the internal P-channel MOS driver transistor is forced OFF when input voltage becomes 1.4V or lower. The B to G types integrate C discharge function which enables the electric charge at the output capacitor C to be discharged L L via the internal discharge switch located between the L and V pins. When the devices enter stand-by mode, output voltage X SS quickly returns to the V level as a result of this function. SS Four types of package SOT-25, USP-6C, USP-6EL and WLP-5-03 are available. APPLICATIONS FEATURES Smart phones / Mobile phones Driver Transistor Built-In : 0.42 P-ch driver transistor 0.52 N-ch switch transistor Bluetooth Input Voltage : 2.0V ~ 6.0V (A/B/C types) Mobile devices / terminals 1.8V ~ 6.0V (D/E/F/G types) Portable game consoles Output Voltage : 0.8V ~ 4.0V (Internally set) Digital still cameras / Camcorders 0.9V ~ 6.0V (Externally set) Note PCs / Tablet PCs High Efficiency : 92% (TYP.)* Output Current : 600mA Oscillation Frequency : 1.2MHz, 3.0MHz (+15%) Maximum Duty Cycle : 100% Control Methods : PWM (XC9235) PWM/PFM Auto (XC9236) PWM/PFM Manual (XC9237) TYPICAL APPLICATION CIRCUIT Function : Current Limiter Circuit Built-In (Constant Current & Latching) XC9235/XC9236/XC9237 C Discharge (B/C/D/E/F/G types) L / / High Speed Soft Start (B/F/G type) A/B/C/E/G types (Output Voltage Fixed) , , , , () Capacitor : Low ESR Ceramic Capacitor VOUT L Operating Ambient Temperature :-40 ~ +85 600mA VIN Lx VIN Packages : SOT-25 (A/B/C types only) VSS USP-6C VSS CIN (ceramic) USP-6EL (A/B/C/G types only) CL CE/ VOUT (ceramic) MODE WLP-5-03 (A/B types only) CE/MODE Environmentally Friendly : EU RoHS Compliant, Pb Free * Performance depends on external components and wiring on the PCB. TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs. Output Current (f =1.2MHz, VOUT=1.8V) OSC XC9235/XC9236/XC9237 XC9235/9236/9237 PWM/PFM Automatic Sw itching Control 100 / / D/F types (Output Voltage Externally Set) D,F() 90 , () VOUT 80 L VOUT 600mA VIN L VIN= 4.2V 70 600mA VIN Lx VIN VIN Lx 3.6V PWM Control 60 VSS VSS VIN= 4.2V RFB1 CIN 2.4V 50 VSS VSS CIN RFB1 3.6V CL CFB 40 2.4V (ceramic) (ceramic) CE/ 30 FB MODE CE/MODE 20 RFB2 10 0 0.1 1 10 100 1000 Output Current:IOUT(mA) 1/40 Efficiency: EFFI (%) Efficency:EFFI(%) XC9235/XC9236/XC9237 Series BLOCK DIAGRAM XC9235 / XC9236 / XC9237 A Series XC9235 / XC9236 / XC9237 B/C/E/G Phase Phase Compensation Compensation Current Feedback Current Feedback VOUT CFB VOUT CFB Current Limit Current Limit R2 R2 Error Amp. Error Amp. PWM PWM Comparator Comparator Synch Synch FB FB Buffer Logic Logic Buffer R1 R1 Lx Lx Drive Drive VSHORT VSHORT VIN VIN Vref with Vref with PWM/PFM PWM/PFM Soft Start, Soft Start, Selector Selector CE CE CE/ Ramp Wave Ramp Wave UVLO Cmp UVLO Cmp Generator Generator OSC OSC R3 UVLO R3 UVLO VSS VSS CE/MODE CE/MODE R4 R4 Control Control CE/MODE CE/MODE Logic Logic XC9235 / XC9236 / XC9237 D/F Series Phase Compensation Current Feedback FB Current Limit Error Amp. PWM Comparator Synch FB Logic Buffer Lx Drive VSHORT VIN Vref with PWM/PFM Soft Start, Selector CE CE/ Ramp Wave UVLO Cmp Generator UVLO OSC R3 VSS CE/MODE R4 Control CE/MODE Logic NOTE: The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to level inside, and XC9235 series chooses only PWM control. The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to level inside, and XC9236 series chooses only PWM/PFM automatic switching control. Diodes inside the circuit are ESD protection diodes and parasitic diodes. 2/33