XC9272 Series ETR05057-003 Ultra Low Quiescent Current Synchronous Step-Down PFM DC/DC Converter for Low Output Voltage GreenOperation compatible GENERAL DESCRIPTION XC9272 series are Ultra Low Quiescent Current synchronous-rectification for Low Output Voltage type PFM step down DC/DC converters with a built-in 0.4 (TYP.) Pch driver and 0.4 (TYP.) Nch synchronous switching transistor, designed to allow the use of ceramic capacitor. PFM control enables a low quiescent current, making these products ideal for battery operated devices that require high efficiency and long battery life. Only inductor, CIN and CL capacitors are needed as external parts to make a step down DC/DC circuit. Operation voltage range is from 2.0V to 6.0V. This product has fixed output voltage from 0.6V to 0.95V(accuracy: 20mV) in increments of 0.05V. During stand-by, all circuits are shutdown to reduce consumption to as low as 0.1 A(TYP.) or less. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel MOS driver transistor is forced OFF when input voltage gets lower than UVLO detection voltage. Besides, XC9272 series has UVLO release voltage of 1.8V (Typ.). The product with CL discharge function, XC9272B type, can discharge CL capacitor during stand-by mode due to the internal resistance by turning on the internal switch between VOUT -GND. This enables output voltage restored to GND level fast. APPLICATIONS FEATURES Input Voltage Range : 2.0V~6.0V Electric devices with GPS Output Voltage Setting : 0.6V~0.95V (20mV, 0.05V step increments) Wearable devices Output Current : 50mA Energy Harvest devices Driver Transistor : 0.4 (Pch Driver Tr) 0.4 (Nch Synchronous rectifier Switch Tr) Backup power supply circuits Supply Current : 0.50A VOUT(T)=0.7V (TYP.) Devices with 1 Lithium cell Control Method : PFM control High Speed Transient : 50mV (VIN=3.6V, VOUT=0.7V, IOUT=10A50mA) PFM Switching Current : 180mA Function : Short Protection function CL Discharge(XC9272B type) UVLO function Ceramic Capacitor Compatible Operation Ambient Temperature : -40+85 Package : SOT-25, USP-6EL Environmentally Friendly : EU RoHS compliant, Pb Free TYPICAL PERFORMANCE TYPICAL APPLICATION CIRCUIT CHARACTERISTICS Efficiency vs. Output Current XC9272A071xR-G(V =0.7V) OUT L=10H(VLF302512M-100M),C =10F(LMK107BJ106MA), IN C =22F(JMK107BJ226MA) L 100 L VIN=2.0V V IN VOUT V L IN X 80 C IN C L 60 (Ceramic) V CE OUT (Ceramic) VIN=3.6V GND 40 20 0 0.01 0.1 1 10 100 Output Current : I (mA) OUT 1/24 Ef f iciency : EFFI (%) XC9272 Series BLOCK DIAGRAM XC9272A Type PFM Comparator Unit V OUT C R FB FB1 Short Current protection Sense PFM R FB2 Comparator FB - + PFM Controller Synch Buffer L X CE CE Controller Logic V Driver REF V DD GND UVLO V IN V start up IN Controller * Diodes inside the circuit are an ESD protection diode and a parasitic diode. XC9272B Type PFM Comparator Unit V OUT C R FB FB1 Short Current protection Sense CL Discharge PFM R FB2 Comparator FB - + PFM Controller Synch Buffer L X CE CE Controller Logic V REF Driver V DD GND UVLO V IN VIN start up Controller * Diodes inside the circuit are an ESD protection diode and a parasitic diode. 2/24