RT9266B Tiny Package, High Efficiency, Step-Up DC/DC Converter General Description Features The RT9266B is a compact, high efficiency, and low voltage step-up DC/DC converter with an Adaptive Current Mode PWM control loop, includes an error amplifier, ramp generator, comparator, switch pass element and driver in which providing a stable and high efficient operation over a wide range of load currents. It operates in stable waveforms without external compensation. z The low start-up input voltage below 1V makes RT9266B suitable for 1 to 4 battery cells applications with a 500mA internal switch. The 550kHz high switching rate minimized the size of external components. Besides, the 25μA low quiescent current together with high efficiency maintains long battery lifetime. z z z z z z z z z z Ordering Information z RT9266B z z Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Zero Shutdown Mode Supply Current 90% Efficiency 550kHz Switching Frequency at 3.3V VDD Providing Flexibility for Using Internal and External Power Switches Small SOT-23-6 Package RoHS Compliant and 100% Lead (Pb)-Free Applications z Package Type E : SOT-23-6 1V Low Start-up Input Voltage at 1mA Load 25μ μA Quiescent (Switch-off) Supply Current PDA DSC LCD Panel RF-Tags MP3 Portable Instrument Wireless Equipment Pin Configurations (TOP VIEW) Note : Richtek products are : ` RoHS compliant and compatible with the current require- ` Suitable for use in SnPb or Pb-free soldering processes. ments of IPC/JEDEC J-STD-020. FB VDD LX 6 5 4 2 3 EN EXT GND SOT-23-6 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS9266B-11 April 2011 www.richtek.com 1 RT9266B Typical Application Circuit L1 VIN D1 3.3 to 10 uH C3 10uF SS0520 VOUT 3.3V/5V C2 1uF R1 1.6M/3M VDD EN RT9266B EXT GND LX FB R2 980k/1M C1 10uF Figure 1. RT9266B Typical Application for Portable Instruments L1 VIN C3 10uF D1 3.3 to 10 uH VOUT 3.3V/5V SS0520 C2 1uF VDD EN LX Q1 N MOS RT9266B EXT GND R1 1.6M/3M C1 10uF FB R2 980k/1M Figure 2. RT9266B for Higher Current Applications Test Circuit I (VIN) A L1 D1 10uH + VIN C3 10uF A I (VDD) SS0520 VOUT 3.3V/5V C2 1uF R1 1.6M/3M VDD EN RT9266B LX EXT GND FB C4 100p C5 10uF R2 980k/1M www.richtek.com 2 DS9266B-11 April 2011 RT9266B Functional Pin Description Pin Name Pin Function EN Chip Enable (Active High) EXT Output Pin for Driving External NMOS GND Ground LX Pin for Switching VDD Input Positive Power Pin of RT9266B FB Feedback Input Pin Internal Reference Voltage for the Error Amplifier is 1.25V. Function Block Diagram EXT RT9266B VDD LX1 - FB + 1.25V Loop Control Circuit VDD Q1 N MOS R1 R2 Shut Down EN DS9266B-11 April 2011 Q3 N MOS Over Temp. Detector GND www.richtek.com 3 RT9266B Absolute Maximum Ratings z z z z z z z z Supply Voltage --------------------------------------------------------------------------------------------------- −0.3V to 7V LX Pin Switch Voltage ------------------------------------------------------------------------------------------ −0.3V to 6.5V Other I/O Pin Voltages ------------------------------------------------------------------------------------------ −0.3V to (VDD + 0.3V) LX Pin Switch Current ------------------------------------------------------------------------------------------ 2.5A EXT Pin Driver Current ------------------------------------------------------------------------------------------ 200mA Package Thermal Resistance SOT-23-6, θJC ----------------------------------------------------------------------------------------------------- 145°C/W Operating Junction Temperature ------------------------------------------------------------------------------ 125°C Storage Temperature Range ----------------------------------------------------------------------------------- −65°C to +150°C Electrical Characteristics (VIN = 1.5V, VDD set to 3.3V, Load Current = 0, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Start-UP Voltage VST IL = 1mA -- 0.98 1.05 V Operating VDD Range VDD VDD pin voltage 2 -- 6.5 V No Load Current I (V IN) INO LOAD VIN = 1.5V, VOUT = 3.3V -- 150 -- μA Switch-off Current I (V DD) ISWITCH OFF VIN = 6V -- 25 -- μA Shutdown Current I (V IN) IOFF EN Pin = 0V, VIN = 4.5V -- 0.01 1 μA Feedback Reference Voltage VREF Close Loop, V DD = 3.3V 1.225 1.25 1.275 V Switching Frequency FS VDD = 3.3V -- 550 -- kHz Maximum Duty DMAX VDD = 3.3V -- 95 -- % VDD = 3.3V -- 0.35 -- Ω VDD = 3.3V -- 0.5 -- A Current Limit Delay Time VDD = 3.3V -- 300 -- ns EXT ON Resistance to VDD VDD = 3.3V -- 5 -- Ω EXT ON Resistance to GND VDD = 3.3V -- 5 -- Ω LX ON Resistance Current Limit Setting ILIMIT Line Regulation (refer to VFB ) ΔV LINE VIN = 1.5 ~ 2.5V, IL = 50mA -- 12 -- mV/V Load Regulation (refer to V FB) ΔV LOAD VIN = 2.5V, IL = 1 ~ 100mA -- 0.25 -- mV/mA 0.4 0.8 1.2 V EN Pin Trip Level VDD = 3.3V Temperature Stability for Vout TS -- 50 -- ppm/°C Thermal Shutdown TSD -- 165 -- °C Thermal Shutdown Hysteresis ΔT SD -- 10 -- °C www.richtek.com 4 DS9266B-11 April 2011 RT9266B Typical Operating Characteristics Efficiency vs. Output Current Efficiency vs. Output Current 95 100 VIN = 3V VIN = 2.5V VIN = 2V VIN = 1.5V Efficiency (%) 85 VIN = 1V 80 VIN = 4.5V VIN = 4V VIN = 3.5V VIN = 3V VIN = 2.5V VIN = 2V VIN = 1.5V 90 Efficiency (%) 90 75 70 80 70 65 VOUT = 3.3V, TA = 25°C VOUT = 5V, TA = 25°C 60 60 1 10 100 1000 1 10 Output Current (mA) 5.1 VIN = 4.5V Output Voltage (V) 5.05 3.32 VIN = 3V VIN = 2.5V 3.28 VIN = 2V 3.24 VIN = 1.5V VIN = 4V 5 VIN = 3.5V 4.95 VIN = 3V VIN = 1.5V VIN = 2.5V 4.9 VIN = 1V VIN = 2V VOUT = 3.3V, TA = 25°C VOUT = 5V, TA = 25°C 3.2 4.85 1 10 100 1000 1 10 Output Current (mA) 100 1000 Output Current (mA) Input Current vs. Input Voltage Input Current vs. Input Voltage 350 800 300 700 Input Current (uA) Input Current (uA) 1000 Output Voltage vs. Output Current Output Voltage vs. Output Current 3.36 Output Voltage (V) 100 Output Current ( mA) 250 200 150 100 50 600 500 400 300 200 100 VOUT = 3.3V @ no load VOUT = 5V @ no load 0 0 1 1.5 2 Input Voltage (V) DS9266B-11 April 2011 2.5 3 1 2 3 4 5 Input Voltage (V) www.richtek.com 5 RT9266B LX (V) LX & Output Ripple LX & Output Ripple VIN = 1.5V, VOUT = 3.3V @ 100mA Time (1us/Div) LX & Output Ripple LX & Output Ripple LX (V) Time (1us/Div) VIN = 2V, VOUT = 3.3V @ 10mA Output Ripple (mV) Output Ripple (mV) VIN = 1.5V, VOUT = 3.3V @ 10mA Output Ripple (mV) LX (V) Time (1us/Div) LX (V) Output Ripple (mV) VIN = 1V, VOUT = 3.3V @ 50mA Time (1us/Div) Time (1us/Div) www.richtek.com 6 LX & Output Ripple Output Ripple (mV) VIN = 1V, VOUT = 3.3V @ 10mA LX (V) Output Ripple (mV) LX (V) LX & Output Ripple VIN = 2V, VOUT = 3.3V @ 100mA Time (1us/Div) DS9266B-11 April 2011 RT9266B LX (V) LX & Output Ripple VIN = 2.5V, VOUT = 3.3V @ 10mA Output Ripple (mV) Output Ripple (mV) LX (V) LX & Output Ripple VIN = 2.5V, VOUT = 3.3V @ 100mA Time (1us/Div) LX & Output Ripple LX & Output Ripple VIN = 3V, VOUT = 3.3V @ 10mA Output Ripple (mV) Output Ripple (mV) LX (V) LX (V) Time (1us/Div) VIN = 3V, VOUT = 3.3V @ 100mA Time (1us/Div) LX & Output Ripple LX & Output Ripple VIN = 1.5V, VOUT = 5V @ 10mA Time (1us/Div) DS9266B-11 April 2011 Output Ripple (mV) Output Ripple (mV) LX (V) LX (V) Time (1us/Div) VIN = 1.5V, VOUT = 5V @ 80mA Time (1us/Div) www.richtek.com 7 RT9266B LX (V) Time (1us/Div) LX & Output Ripple LX & Output Ripple LX (V) Output Ripple (mV) VIN = 2.5V, VOUT = 5V @ 100mA Time (1us/Div) Time (1us/Div) LX & Output Ripple LX & Output Ripple LX (V) VIN = 3V, VOUT = 5V @ 10mA Output Ripple (mV) Output Ripple (mV) VIN = 2.5V, VOUT = 5V @ 10mA LX (V) Output Ripple (mV) VIN = 2V, VOUT = 5V @ 100mA Time (1us/Div) Time (1us/Div) www.richtek.com 8 LX & Output Ripple Output Ripple (mV) VIN = 2V, VOUT = 5V @ 10mA LX (V) Output Ripple (mV) LX (V) LX & Output Ripple VIN = 3V, VOUT = 5V @ 100mA Time (1us/Div) DS9266B-11 April 2011 RT9266B LX & Output Ripple VIN = 3.5V, VOUT = 5V @ 10mA Output Ripple (mV) Output Ripple (mV) LX (V) LX (V) LX & Output Ripple VIN = 3.5V, VOUT = 5V @ 100mA Time (1us/Div) LX & Output Ripple LX & Output Ripple VIN = 4V, VOUT = 5V @ 10mA Output Ripple (mV) Output Ripple (mV) LX (V) LX (V) Time (1us/Div) VIN = 4V, VOUT = 5V @ 100mA Time (1us/Div) LX & Output Ripple LX & Output Ripple VIN = 4.5V, VOUT = 5V @ 10mA Time (5us/Div) DS9266B-11 April 2011 Output Ripple (mV) Output Ripple (mV) LX (V) LX (V) Time (2.5us/Div) VIN = 4.5V, VOUT = 5V @ 100mA Time (1us/Div) www.richtek.com 9 RT9266B Load Transient Respones Load Transient Respones Load Transient Respones VIN = 3V, VOUT = 5V, IOUT = 10mA to 100mA Time (2.5ms/Div) Load Transient Respones Load Transient Respones Output Voltage (mV) Time (2.5ms/Div) VIN = 3.5V, VOUT = 5V, IOUT = 10mA to 100mA Output Current (mA) Output Current (mA) VIN = 3V, VOUT = 3.3V, IOUT = 10mA to 100mA Output Current (mA) Output Voltage (mV) Time (2.5ms/Div) Output Voltage (mV) Output Current (mA) VIN = 1.5V, VOUT = 3.3V, IOUT = 10mA to 100mA Time (2.5ms/Div) Time (2.5ms/Div) www.richtek.com 10 Output Current (mA) VIN = 1V, VOUT = 3.3V, IOUT = 10mA to 50mA Output Voltage (mV) Output Current (mA) Output Voltage (mV) Output Voltage (mV) Load Transient Respones VIN = 4.2V, VOUT = 5V, IOUT = 10mA to 100mA Time (2.5ms/Div) DS9266B-11 April 2011 RT9266B Switching Frequency vs. VDD Pin Voltage Switching Frequency (kHz) 1 700 600 500 400 300 VDD = EN FB = GND TA = 25°C 200 100 0 1 2 3 4 5 6 VDD Pin Voltage (V) DS9266B-11 April 2011 www.richtek.com 11 RT9266B Application Information Output Voltage Setting Layout Guide Referring to application circuits, the output voltage of the switching regulator (VOUT) can be set with Equation (1). VOUT1 = ( 1+ R1 R2 ) × 1.25V z z (1) z Feedback Loop Design Referring to application circuits, The selection of R1 and R2 based on the trade-off between quiescent current consumption and interference immunity is stated below: z Follow Equation (1). z Higher R reduces the quiescent current (Path current = 1.25V/R2), however resistors beyond 5MΩ are not recommended. z A full GND plane without gap break. VDD to GND noise bypass − Short and wide connection for the 1mF MLCC capacitor between Pin5 and Pin3. VIN to GND noise bypass − Add a capacitor close to L1 inductor, when VIN is not an idea voltage source. z Minimized FB node copper area and keep far away from noise sources. z Minimized parasitic capacitance connecting to LX and EXT nodes, which may cause additional switching loss. Board Layout Example (2-Layer Board) (Refer to Application Circuit Figure 2 for the board) Lower R gives better noise immunity, and is less sensitive to interference, layout parasitics, FB node leakage, and improper probing to FB pins. VOUT1 Prober Parasitics R1 FB Pin _ Q + z R2 A proper value of feed forward capacitor parallel with R1 can improve the noise immunity of the feedback loops, especially in an improper layout. An empirical suggestion is around 0~33pF for feedback resistors of MΩ, and 10nF~0.1μF for feedback resistors of tens to hundreds kΩ. - Top Layer - For applications without standby or suspend modes, lower values of R1 and R2 are preferred. For applications concerning the current consumption in standby or suspend modes, the higher values of R1 and R2 are needed. Such “ high impedance feedback loops” are sensitive to any interference, which require careful layout and avoid any interference, e.g. probing to FB pin. - Bottom Layer - www.richtek.com 12 DS9266B-11 April 2011 RT9266B Outline Dimension H D L C B b A A1 e Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.889 1.295 0.031 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.250 0.560 0.010 0.022 C 2.591 2.997 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 SOT-23-6 Surface Mount Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: [email protected] Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. DS9266B-11 April 2011 www.richtek.com 13