RT9261B Preliminary VFM Step-Up DC/DC Converter General Description Features The RT9261B Series are VFM Step-up DC/DC converter ICs with ultra low supply current by CMOS process and suitable for use with battery-powered instruments. z The RT9261B IC consists of an oscillator, a VFM control circuit, a driver transistor (LX switch), a reference voltage unit, an error amplifier, resistors for voltage detection, and a LX switch protection circuit. A low ripple and high efficiency step-up DC/DC converter can be constructed with the RT9261B IC and only three external components. z z z z z z z The EN pin enables the circuit to set the standby supply current at a maximum of 0.5μA. Ordering Information RT9261BPackage Type B : SOT-23-5 X : SOT-89 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) Output Voltage 15 : 1.5V 16 : 1.6V : 49 : 4.9V 50 : 5.0V z z Minimal Number of External Components (Only an Inductor, a Diode, and a Capacitor) Ultra Low Input Current (6.5μ μA at Switch Off) Capable of Supplying 50mA Output Current with Internal Switch ± 2% Output Voltage Accuracy Low Ripple and Low Noise Low Start-up Voltage, 0.8V at 1mA 80% Efficiency with Low Cost Inductor +50 ppm/° C Low Temperature-Drift SOT-89 and SOT-23-5 Small Packages RoHS Compliant and 100% Lead (Pb)-Free Applications z z z Power source for battery-powered equipment Power source for cameras, camcorders, VCRs, PDAs, pagers, electronic data banks, and hand-held communication equipment Power source for appliances, which require higher voltage than that of batteries used in the appliances Pin Configurations (TOP VIEW) EN 1 VOUT 2 NC 3 5 LX 4 GND Note : RichTek Pb-free and Green products are : `RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. `Suitable for use in SnPb or Pb-free soldering processes. SOT-23-5 `100% matte tin (Sn) plating. Marking Information For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail. 1 2 GND VOUT (TAB) 3 LX SOT-89 DS9261B-12 March 2007 www.richtek.com 1 RT9261B Preliminary Typical Application Circuit D1 1N5819 L1 VIN + RT9261B LX VOUT GND COUT 22uF VOUT D1 1N5819 L1 VIN EN RT9261B VOUT + LX GND VOUT COUT 22uF * L1 ranges from 27μH to 120μH Functional Pin Description Pin No. Pin Name Pin Function -xxCX -xxCB 1 4 GND Ground 2 2 VOUT Output Voltage 3 5 LX Pin for Switching -- 1 EN Chip Enable (Active High) -- 3 NC No Connection Function Block Diagram VLX Limiter LX VREF LXSW Buffer VOUT GND OSC 190kHz + Error Amplifier Chip Enable EN www.richtek.com 2 DS9261B-12 March 2007 RT9261B Preliminary Absolute Maximum Ratings z z z z z z z z z Output Voltage -------------------------------------------------------------------------------------------------------LX Pin Voltage --------------------------------------------------------------------------------------------------------EN Pin Voltage(1) -----------------------------------------------------------------------------------------------------LX Pin Output Current ----------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOT-89 -----------------------------------------------------------------------------------------------------------------SOT-23-5 --------------------------------------------------------------------------------------------------------------Package Thermal Resistance SOT-89, θJC -----------------------------------------------------------------------------------------------------------SOT-89, θJA -----------------------------------------------------------------------------------------------------------SOT-23-5, θJA ---------------------------------------------------------------------------------------------------------Operating Temperature Range ------------------------------------------------------------------------------------Storage Temperature Range --------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- 8V 8V −0.3 to VOUT +0.3V 400mA 0.5W 0.25W 100° C/W 300° C/W 250° C/W −20 to +85°C −65°C to 150°C 260°C Notes: (1) Applicable to RT9261B-xxCB Electrical Characteristics (Refer to Figure 1) Parameter Symbol Test Conditions Min Typ Max Units Output Voltage Accuracy ΔVOUT -2 -- +2 % Input Voltage VIN -- -- 7 V Start-up Voltage VST IOUT = 1mA, VIN: 0 → 2V -- 0.8 1 V Hold-on Voltage VHO IOUT = 1mA, VIN: 2 → 0V 0.7 -- -- V To be measured at VIN in continuous switching -- 24 36 -- 36 45 -- 6.5 10 -- 18 36 -- 20 45 120 -- -- 160 -- -- -- -- 0.5 μA VOUT = 2.5V to 5V 140 190 240 kHz VOUT = 1.5V to 2.4V 140 190 320 kHz On (VLX “L”) side 65 75 85 % -- 80 -- % 0.65 0.8 1.0 V VOUT ≤ 3.5V Input Current 1 Input Current 2 (1) 3.5V < VOUT ≤ 5V (2) To be measured at VOUT in switch off condition (1) (2) Input Current 3 VOUT ≤ 3.5V (1) 3.5V < VOUT ≤ 5V LX Switching Current VOUT ≤ 3.5V To be measured at VIN in no load (guaranteed by I1 and I2) (2) (1) 3.5V < VOUT ≤ 5V (2) ISWITCHING VLX = 0.4V LX Leakage Current ILEAKAGE Maximum Oscillator Frequency FMAX Oscillator Duty Cycle DOSC VLX = 6V Efficiency VLX Voltage Limit LX switch on μA μA μA mA Notes: (1) VIN = 1.8V, VSS = 0V, IOUT = 1mA, Topt = 25° C, and use External Circuit of Typical Application (2) VIN = 3V, VSS = 0V, IOUT = 1mA, Topt= 25°C, and External Circuit of Typical Application DS9261B-12 March 2007 www.richtek.com 3 RT9261B Preliminary Electrical Characteristics (Refer to Figure 2) Parameter Symbol Test Conditions Min Typ Max Units Output Voltage Accuracy ΔVOUT -2 -- +2 % Input Voltage VIN -- -- 7 V Start-up Voltage VST IOUT = 1mA, VIN: 0 → 2V -- 0.8 1 V Hold-on Voltage VHO IOUT = 1mA, VIN: 2 → 0V 0.7 -- -- V -- 80 -- % -- 24 36 -- 36 45 μA -- 6.5 10 -- 18 36 -- 20 45 120 -- -- 160 -- -- -- -- 0.5 μA Efficiency VOUT ≤ 3.5V Input Current 1 Input Current 2 (1) 3.5V < VOUT ≤ 5V To be measured at VIN in continuous switching (2) To be measured at VOUT in switch off condition (1) (2) Input Current 3 LX Switching Current VOUT ≤ 3.5V (1) 3.5V < VOUT ≤ 5V VOUT ≤ 3.5V (2) (1) 3.5V < VOUT ≤ 5V LX Leakage Current To be measured at VIN in no load (guaranteed by I1 and I2) (2) ISWITCHING VLX = 0.4V ILEAKAGE VLX = 6V μA μA mA EN “H” Level VIN = VOUT * 0.9 0.4×VOUT -- -- V EN “L” Level VIN = VOUT * 0.9 -- -- 0.2 V EN “H” Input Current EN = VOUT -- -- 0.5 μA EN “ L” Input Current EN = 0V -0.5 -- -- μA VOUT = 2.5V to 5V 140 190 240 kHz VOUT = 1.5V to 2.4V 140 190 320 kHz On (VLX “L”) side 65 75 85 % 0.65 0.8 1.0 V Maximum Oscillator Frequency Oscillator Duty Cycle VLX Voltage Limit FMAX DOSC LX switch on Notes: (1) VIN = 1.8V, VSS = 0V, IOUT = 1mA, Topt = 25°C, and use External Circuit of Typical Application (2) VIN = 3V, VSS = 0V, IOUT = 1mA, Topt= 25°C, and External Circuit of Typical Application www.richtek.com 4 DS9261B-12 March 2007 RT9261B Preliminary Output Voltage vs. Output Current Start-up/Hold-on Voltage vs. Output Current 4.0 2.5 3.0V 2.5V 3.5 2 Output Voltage (V) 1 Start-up/Hold-on Voltage Vstart/Vhold (V)1 Typical Operating Characteristics 1.5 Vstart 1 Vhold 0.5 VOUT = 3.3V L = 47uH 3.0 2.0V 1.5V 1.0V 2.5 2.0 1.5 1.0 VOUT = 3.3V 0.5 0 0.0 0 30 60 90 120 150 180 0 50 Output Current (mA) 100 150 200 Output Current (mA) Output Current vs. Ripple Voltage Output Current vs. Ripple Voltage 90 300 2.5V 3.0V 250 2.0V 3.0V 200 150 1.5V 100 VOUT = 3.3V COUT = 20uF L = 47uH 50 1.0V Ripple Voltage (mVp-p)1 Ripple Voltage (mVp-p) 1 80 70 2.0V 60 2.5V 50 40 30 1.5V 20 10 0 VOUT = 3.3V COUT = 68uF L = 47uH 1.0V 0 0 50 100 150 200 0 50 Output Current (mA) 100 150 200 Output Current (mA) Efficiency vs. output Current Output Current vs. Ripple Voltage 90 25 3.0V 2.5V 20 70 2.5V 3.0V 15 10 1.0V VOUT = 3.3V COUT = 170uF L = 47uH 5 2.0V 1.5V 0 0 50 1.0V 2.0V 1.5V 60 50 40 30 20 VOUT = 3.3V 10 0 100 150 Output Current (mA) DS9261B-12 March 2007 Efficiency (%)1 Ripple Voltage (mVp-p)1 80 200 0 50 100 150 200 Output Current (mA) www.richtek.com 5 Preliminary Output Voltage vs. Output Current Start-up/Hold-on Voltage vs. Output Current 2.5 4.0 3.0V 3.5 2 Output Voltage (V) 1 Start-up/Hold-on Voltage Vstart/Vhold (V)1 RT9261B 1.5 Vstart 1 Vhold 0.5 VOUT = 3.3V 1.5V 3.0 2.5 2.0 1.5 1.0 VOUT = 3.3V 0.5 0.0 0 0 20 40 60 80 100 0 120 50 Output Current vs. Ripple Voltage 2.0V 200 Output Current vs. Ripple Voltage 3.0V 250 200 2.5V 150 100 VOUT = 3.3V COUT = 20uF L = 100uH 50 1.5V 1.0V 0 0 50 2.5V 80 Ripple Voltage (mVp-p) 1 Ripple Voltage (mVp-p) 1 150 90 300 70 60 50 3.0V 40 30 20 2.0V 1.5V 0 100 150 VOUT = 3.3V COUT = 68uF L = 100uH 1.0V 10 0 200 50 Output Current (mA) 100 150 Efficiency vs. output Current 100 2.5V 90 16 3.0V Efficiency (%) 1 12 1.0V 8 6 4 2 VOUT = 3.3V COUT = 170uF L = 100uH 1.5V 3.0V 80 2.0V 14 200 Output Current (mA) Output Current vs. Ripple Voltage 18 Ripple Voltage (mVp-p) 1 100 Output Current (mA) Output Current (mA) 10 2.5V 2.0V 1.0V 1.0V 70 2.5V 2.0V 1.5V 60 50 40 30 20 VOUT = 3.3V 10 0 0 0 50 100 150 Output Current (mA) www.richtek.com 6 200 0 50 100 150 200 Output Current (mA) DS9261B-12 March 2007 RT9261B Preliminary Outline Dimension H D L B C b A A1 e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.889 1.295 0.035 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.356 0.559 0.014 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-23-5 Surface Mount Package DS9261B-12 March 2007 www.richtek.com 7 RT9261B Preliminary D D1 A B C C1 e e H A b Symbol b1 b Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 1.397 1.600 0.055 0.063 b 0.356 0.483 0.014 0.019 B 2.388 2.591 0.094 0.102 b1 0.406 0.533 0.016 0.021 C 3.937 4.242 0.155 0.167 C1 0.787 1.194 0.031 0.047 D 4.394 4.597 0.173 0.181 D1 1.397 1.753 0.055 0.069 e 1.448 1.549 0.057 0.061 H 0.356 0.432 0.014 0.017 3-Lead SOT-89 Surface Mount Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)89191466 Fax: (8862)89191465 Email: [email protected] www.richtek.com 8 DS9261B-12 March 2007