RT9261/A VFM Step-Up DC/DC Converter General Description Features The RT9261 Series are VFM Step-up DC/DC ICs with ultra low supply current by CMOS process and suitable for use with battery-powered instruments. z The RT9261 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 of this RT9261 IC with only three external components. z z z z z z z z The RT9261A IC provides with a drive pin (EXT) for an external transistor, so that a power transistor can be externally applied. Therefore, the RT9261A IC is recommended for applications where large currents are required. EN pin enables circuit to set the standby supply current at a maximum of 0.5A. Ordering Information RT9261/APackage Type B : SOT-23-5 X : SOT-89 Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Output Voltage 15 : 1.5V 16 : 1.6V : 49 : 4.9V 50 : 5.0V Use external switch Use internal switch Minimal Number of External Components ( Only an Inductor, a Diode, and a Capacitor) Ultra Low Input Current ( 5 A at Switch Off) 2% High Output Voltage Accuracy Low Ripple and Low Noise Low Start-up Voltage, 0.85V at 1mA 75% 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 applications, which require higher voltage than that of batteries used in the appliances Pin Configurations (TOP VIEW) 1 2 3 GND VOUT (TAB) 1 LX 2 3 GND VOUT EXT (TAB) RT9261 RT9261A SOT-89 Note : Richtek products are : ments of IPC/JEDEC J-STD-020. LX GND EXT GND 5 4 5 4 RoHS compliant and compatible with the current requireSuitable for use in SnPb or Pb-free soldering processes. Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS9261/A-16 April 2011 2 3 2 3 EN VOUT NC EN VOUT NC RT9261 RT9261A SOT-23-5 www.richtek.com 1 RT9261/A Typical Application Circuit L1 D1 L1 1N5819 27H VIN 1N5819 Cb 0.01F VOUT RT9261AxX EXT VOUT GND VIN COUT 22F ZTX 650 Tr Rb 300 Figure 1 L1 RT9261xB LX VOUT VOUT VIN Cb 0.01F COUT RT9261AxB VOUT COUT 22F EXT 22F ZTX 650 GND Tr Rb 300 Figure 3 EN VOUT + NC EN 1N5819 NC + VIN VOUT D1 27H 1N5819 100H COUT 22F Figure 2 D1 L1 + 100H + RT9261xX LX VOUT GND D1 GND Figure 4 D1 1N5819 L1 27H VIN NC Chip Enable EN + RT9261xB LX VOUT VOUT COUT 22F GND Figure 5 www.richtek.com 2 DS9261/A-16 April 2011 RT9261/A Functional Pin Description Pin No. RT9261- X RT9261A- X RT9261- B R T9261A-B Pin Name Pin Function 1 1 4 4 GND Ground. 2 2 2 2 VOUT Output Voltage. 3 -- 5 -- LX Pin for Switching. -- 3 -- 5 EXT Drive External Device. -- -- 1 1 EN Chip Enable (Active High). -- -- 3 3 NC No Internal Connected. Function Block Diagram VLX Limiter LX VREF LXSW Buffer VOUT GND - VFM Control EXT + Error Amplifier OSC 100kHz Chip Enable EN Notes: (1) LX Pin...... only for 9261- (2) EXT Pin.... only for 9261A- (3) EN Pin...... only for 9261- DS9261/A-16 April 2011 xX and 9261xX and 9261AxB and 9261A- xB xB xB www.richtek.com 3 RT9261/A Absolute Maximum Ratings Output Voltage ------------------------------------------------------------------------------------------------------ 8V LX Pin Voltage (1) ------------------------------------------------------------------------------------ 8V (2) z EXT Pin Voltage ------------------------------------------------------------------------------------------------- -0.3 to VOUT +0.3V (3) z EN Pin Voltage --------------------------------------------------------------------------------------------------- -0.3 to VOUT +0.3V (1) z LX Pin Output Current ------------------------------------------------------------------------------------------ 250mA (2) z EXT Pin Current -------------------------------------------------------------------------------------------------- 50mA z Power Dissipation, PD @ TA = 25C SOT-89 ---------------------------------------------------------------------------------------------------------------- 0.5W SOT-23-5 -------------------------------------------------------------------------------------------------------------- 0.25W z Package Thermal Resistance SOT-89, JC ---------------------------------------------------------------------------------------------------------- 100C/W SOT-89, JA ---------------------------------------------------------------------------------------------------------- 300C/W SOT-23-5, JA -------------------------------------------------------------------------------------------------------- 250C/W z Operating Temperature Range ----------------------------------------------------------------------------------- -20 to +85C z Storage Temperature Range -------------------------------------------------------------------------------------- 165C z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------ 260C Notes: (1) Applicable to RT9261xX and RT9261xB (2) Applicable to RT9261AxX and RT9261AxB (3) Applicable to RT9261xB and RT9261AxB z z Electrical Characteristics (Refer to Figure 1) Parameter Symbol Test Conditions Min Typ Max Unit Output Voltage Accuracy VOUT -2 -- 2 % Input Voltage VIN -- -- 7 V Start-up Voltage VST IOUT = 1mA, VIN: 0 2V -- 0.85 1 V Hold-on Voltage VHO IOUT = 1mA, VIN: 2 0V VOUT 3.5V (1) VIN at no load 3.5V < VOUT 5V (2) 0.7 --- -15 18 -18 24 V -- 5 8 Input Current 1 Input Current 2 VOUT in switch off condition LX Switching Current ISWITCHING VLX = 0.4V LX Leakage Current ILEAKAGE VLX = 6V Maximum Oscillator FMAX Oscillator Duty Cycle DOSC On ( VLX " L " ) side Efficiency VLX Voltage Limit LX switch on VOUT 3.5V (1) A A 60 -- -- 80 -- -- -- -- 0.5 A 80 120 160 kHz VOUT = 2.5V to 5V 65 75 85 % VOUT = 1.5V to 2.4V 60 70 80 % -- 75 -- % 0.65 0.8 1 V 3.5V < VOUT 5V (2) mA Notes: (1)Unless otherwise provided, VIN = 1.8V, VSS = 0V, IOUT = 10mA, TOPT = 25C, and External Circuit of Typical Application (2)Unless otherwise provided, VIN = 3V, VSS = 0V, IOUT = 10mA, TOPT = 25C, and External Circuit of Typical Application www.richtek.com 4 DS9261/A-16 April 2011 RT9261/A Electrical Characteristics (Refer to Figure 2) Parameter Symbol Output Voltage Accuracy Input Voltage VOUT VIN Start-up Voltage VST Input Current 1 Input Current 2 Test Conditions IOUT = 1mA, VIN : 0 2V (1) VOUT 3.5V VIN at no load 3.5V < VOUT 5V (2) VOUT 3.5V (1) VOUT in switch off condition 3.5V < VOUT 5V (2) (1) EXT "H" Output Current VEXT = VOUT - 0.4V EXT "L" Output Current VEXT = 0.4V Maximum Oscillator Frequency FMAX Oscillator Duty Cycle DOSC VEXT " H " side VOUT 3.5V (2) 3.5V < VOUT 5V (1) VOUT 3.5V (2) 3.5V < VOUT 5V VOUT = 2.5V to 5V VOUT = 1.5V to 2.4V Min Typ Max Unit -2 -- --- +2 7 % V ---- 0.85 30 60 1.0 50 90 V -- 6 10 -1.5 -2 1.5 2 80 65 60 ----120 75 70 ----160 85 80 A A mA mA kHz % % Notes: (1)Unless otherwise provided, VIN = 1.8V, VSS = 0V, IOUT = 10mA, TOPT = 25 C, and use External Circuit of Typical Application (2)Unless otherwise provided, VIN = 3V, VSS= 0V, IOUT = 10mA, TOPT = 25 C, and External Circuit of Typical Application DS9261/A-16 April 2011 www.richtek.com 5 RT9261/A Electrical Characteristics (Refer to Figure 3) Parameter Output Voltage Accuracy Input Voltage Start-up Voltage Hold-on Voltage Symbol VOUT VIN VST VHO Efficiency Input Current 1 Input Current 2 LX Switching Current ISWITCHING LX Leakage Current ILEAKAGE Test Conditions IOUT = 1mA, VIN : 0 2V IOUT = 1mA, VIN : 2 0V VOUT 3.5V (1) (2) 3.5V < V OUT 5V VOUT 3.5V (1) VIN at no load 3.5V < V OUT 5V (2) (1) VOUT in switch VOUT 3.5V (2) off condition 3.5V < V OUT 5V VOUT 3.5V (1) VLX = 0.4V 3.5V < V OUT 5V (2) VLX = 6V EN "H" Level VIN = VOUT x 0.9 EN " L" Level EN " H" Input Current EN " L" Input Current Maximum Oscillator Frequency FMAX VIN = VOUT x 0.9 EN = VOUT EN = 0V Oscillator Duty Cycle VLX Voltage Limit DOSC On (V LX " L" ) V OUT = 2.5V to 5V side V OUT = 1.5V to 2.4V LX switch on Min Typ Max Unit -2 --0.7 ------60 80 -0.4 x VOUT --- --0.85 -75 85 15 18 5 6 ---- +2 7 1.0 ---18 24 8 10 --0.5 % V V V -- -- V 0.2 0.5 -160 V A -0.5 80 ---120 A kHz 65 60 0.65 75 70 0.8 85 80 1.0 % % V % A A mA A Notes: (1)Unless otherwise provided, VIN = 1.8V, VSS = 0V, IOUT = 10mA, TOPT = 25C, and use External Circuit of Typical Application (2)Unless otherwise provided, VIN = 3V, VSS= 0V, IOUT = 10mA, TOPT = 25C, and External Circuit of Typical Application www.richtek.com 6 DS9261/A-16 April 2011 RT9261/A Electrical Characteristics (Refer to Figure 4) Parameter Symbol Test Conditions Min Typ Max Unit Output Voltage Accuracy V OUT -2 -- +2 % Input Voltage VIN -- -- 7 V Start-up Voltage VST IOUT = 1mA, VIN : 0 2V -- 0.85 1.0 V VOUT 3.5V -- 75 -- -- 85 -- -- 30 50 -- 60 90 -- 6 10 -1.5 -- -- -2 -- -- 1.5 -- -- 2 -- -- Efficiency (1) 3.5V < VOUT 5V (2) VOUT 3.5V (1) Input Current 1 VIN at no load Input Current 2 (1) VOUT in switch VOUT 3.5V off condition 3.5V < VOUT 5V (2) EXT "H" Output Current (1) VEXT = VOUT - VOUT 3.5V (2) 0.4V 3.5V < VOUT 5V 3.5V < VOUT 5V VOUT 3.5V (2) (1) % A A mA mA EXT "L" Output Current VEXT = 0.4V EN "H" Level VIN = VOUT x 0.9 0.4x V OUT -- -- V EN " L" Level VIN = VOUT x 0.9 -- -- 0.2 V EN " H" Input Current EN = VOUT -- -- 0.5 A EN " L" Input Current EN = 0V -0.5 -- -- A 80 120 160 kHz VOUT = 2.5V to 5V 65 75 85 % VOUT = 1.5V to 2.4V 60 70 80 % 0.65 0.8 1.0 V Maximum Oscillator Frequency FMAX Oscillator Duty Cycle DOSC V LX Voltage Limit On (V LX " L" ) side LX switch on 3.5V < VOUT 5V (2) Notes: (1)Unless otherwise provided, VIN = 1.8V, VSS = 0V, IOUT = 10mA, TOPT = 25C, and use External Circuit of Typical Application (2)Unless otherwise provided, VIN = 3V, VSS= 0V, IOUT = 10mA, TOPT = 25C, and External Circuit of Typical Application DS9261/A-16 April 2011 www.richtek.com 7 RT9261/A Typical Operating Characteristics Output Current vs. Ripple Voltage Start-up/Hold-on Voltage vs. Output Current 120 1.2 Vstart Ripple Voltage (mV p-p) Start-up/Hold-on Voltage Vstart/Vhold (V) 1.4 1 0.8 Vhold 0.6 0.4 0.2 RT9261 VOUT = 2.7V 100 80 2.0V 60 2.5V 1.5V 40 0.9V 20 0 0 0 10 20 30 40 0 50 20 60 80 100 Output Voltage vs. Temperature Output Voltage vs. Output Current 2.90 3 2.0V 1.5V 2.5 0.9V 2.5V 1.0V 2.85 Output Voltage (V) Output Voltage (V) 40 Output Current (mA) Output Current (mA) 2 1.5 1 0.5 RT9261 VOUT = 2.7V 2.80 2.75 2.70 2.65 RT9261 VOUT = 2.7V 2.60 0 0 20 40 60 80 -40 100 -20 Efficiency vs. Output Current 70 80 2.5V 1.5V 1.0V 0.9V 50 40 30 20 RT9261 VOUT = 2.7V 10 0 Supply Current (uA) 60 2.0V 60 20 40 60 80 Supply Current vs. Temperature 90 70 0 Temperature ( C) Output Current (mA) Efficiency (%) RT9261 VOUT = 2.7V RT9261 VOUT = 2.7V 50 40 30 20 Input Current 2 Input Current 1 10 0 0 20 40 60 Output Current (mA) www.richtek.com 8 80 100 -40 -20 0 20 40 60 80 Temperature ( C) DS9261/A-16 April 2011 Maximum Oscillator Frequency vs. Temperature Output Voltage vs. Output Current 3 160 140 2.5V 1.5V 2.5 120 Output Voltage (V) Maximum Oscillator Frequency (kHz) A RT9261/A 100 80 60 40 1.5 1 0.5 0 RT9261A VOUT = 2.7V 0 -40 -20 0 20 40 60 80 0 30 Temperature ( C) 90 120 150 Efficiency vs. Output Current Oscillator Duty Cycle vs. Temperature 80 2.5V 70 90 60 Efficiency (%) Oscillator Duty Cycle (%) 60 Output Current (mA) 100 80 70 2.0V 0.9V 50 1.5V 1.0V 40 30 20 60 RT9261 VOUT = 2.7V RT9261A VOUT = 2.7V 10 50 0 -40 -20 0 20 40 60 80 0 30 Temperature ( C) 60 90 120 150 Output Current (mA) Start-up/Hold-on Voltage vs. Output Current Output Current vs. Ripple Voltage 1.6 120 1.4 Ripple Voltage (mV p-p) Start-up/Hold-on Voltage1 Vstart/Vhold (V) 2.0V 0.9V 2 RT9261 VOUT = 2.7V 20 1.0V Vstart 1.2 1 0.8 Vhold 0.6 0.4 RT9261A VOUT = 2.7V 0.2 0 100 2.5V 80 2.0V 60 1.5V 40 0.9V 20 RT9261A VOUT = 2.7V 0 0 30 60 90 Output Current (mA) DS9261/A-16 April 2011 120 150 0 30 60 90 120 150 Output Current (mA) www.richtek.com 9 RT9261/A Outline Dimension H D L B C b A A1 e Dimensions In Millimeters Dimensions In Inches Symbol 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 www.richtek.com 10 DS9261/A-16 April 2011 RT9261/A D D1 A B C C1 e e H A b b1 b Dimensions In Millimeters Dimensions In Inches Symbol 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 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: marketing@richtek.com 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. DS9261/A-16 April 2011 www.richtek.com 11