RT9261B Preliminary VFM Step-up DC/DC Converter General Description Features The RT9261B Series are VFM Step-up DC/DC z converter ICs with ultra low supply current by CMOS Minimal Number of External Components (Only an Inductor, a Diode, and a Capacitor) process and suitable for use with battery-powered z Ultra Low Input Current (6.5µ µA at Switch Off) instruments. z Capable of Supplying 50mA Output Current with Internal Switch The RT9261B IC consists of an oscillator, a VFM z control circuit, a driver transistor (LX switch), a z ±2% Output Voltage Accuracy Low Ripple and Low Noise reference voltage unit, an error amplifier, resistors z Low Start-up Voltage, 0.8V at 1mA for voltage detection, and a LX switch protection z 80% Efficiency with Low Cost Inductor circuit. A low ripple and high efficiency step-up z DC/DC converter can be constructed with the +50 ppm/°°C Low Temperature-Drift z SOT-89 and SOT-25 Small Packages RT9261B IC and only three external components. Applications The CE pin enables the circuit to set the standby supply current at a maximum of 0.5µA. z Power source for battery-powered equipment z Power source for cameras, camcorders, VCRs, PDAs, pagers, electronic data banks, and hand- Ordering Information RT9261B- Package type B : SOT-25 X : SOT-89 Operating temperature range C: Commercial standard Output voltage 15 : 1.5V 16 : 1.6V : 49 : 4.9V 50 : 5.0V held communication equipment z Power source for appliances, which require higher voltage than that of batteries used in the appliances Pin Configurations Part Number Pin Configurations TOP VIEW RT9261B- CX 1 RT9261B- CB (Plastic SOT-25) 2 3 TOP VIEW 5 1 DS9261B-03 September 2001 1. GND 2. VOUT (TAB) 3. LX (Plastic SOT-89) 4 2 3 1. 2. 3. 4. CE VOUT NC GND 5. LX www.richtek-ic.com.tw 1 RT9261B Preliminary Typical Application Circuit D1 1N5819 RT9261B LX VOUT GND L1 VIN 27µH VOUT + - Co 22µF D1 1N5819 RT9261B LX VOUT CE GND L1 VIN 27µH VOUT + Co - 22µF * L1 ranges from 27µH to 120µH 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 CE Chip Enable (Active High) -- 3 NC No Connection Function Block Diagram VLX Limiter LX Vref LXSW Buffer GND VFM Control OSC 190kHz VOUT + Error Amp. Chip Enable CE www.richtek-ic.com.tw 2 DS9261B-03 September 2001 RT9261B Preliminary Absolute Maximum Ratings z Output Voltage z LX Pin Voltage 8V 8V (1) z CE Pin Voltage -0.3 to VOUT +0.3V z LX Pin Output Current 400mA z Power Dissipation, PD @ TA = 25°C z SOT-89 0.5W SOT-25 0.25W Package Thermal Resistance SOT-89, θJC 100°C/W SOT-89, θJA 300°C/W SOT-25, θJA 250°C/W z Operating Temperature Range -20 to +85°C z Storage Temperature Range -65°C to 150°C z Lead Temperature (Soldering, 10 sec.) 260°C Notes: (1) Applicable to RT9261B-xxCB Electrical Characteristics (Refer to Fig. 1) Parameter Symbol Test Conditions Min Typ Max Units Output Voltage Accuracy ∆VOUT -2 -- +2 % Input Voltage VIN -- -- 7 V Start-up Voltage VST IOUT = 1mA, VIN: 0 → 2V -- 0.8 1 V 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 140 190 240 KHz 65 75 85 % -- 80 -- % 0.65 0.8 1.0 V Hold-on Voltage 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 On (VLX “L”) side Efficiency VLX Voltage Limit LX switch on µA µA µA mA Notes: (1) VIN = 1.8V, VSS = 0V, IOUT = 1mA, Topt = 25°C, and External Circuit of Typical Application (2) VIN = 3V, VSS = 0V, IOUT = 1mA, Topt = 25°C, and External Circuit of Typical Application DS9261B-03 September 2001 www.richtek-ic.com.tw 3 RT9261B Preliminary Electrical Characteristics (Refer to Fig. 2) Parameter Symbol Test Conditions Min Typ Max Units Output Voltage Accuracy ∆VOUT -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 -- 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 VOUT ≤ 3.5V (1) 3.5V < VOUT ≤ 5V LX Switching Current 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 µA mA CE “H” Level VIN = VOUT * 0.9 0.4×VOUT -- -- V CE “L” Level VIN = VOUT * 0.9 -- -- 0.2 V CE “H” Input Current CE = VOUT -- -- 0.5 µA CE “ L” Input Current CE = 0V -0.5 -- -- µA 140 190 240 KHz 65 75 85 % 0.65 0.8 1.0 V Maximum Oscillator Frequency FMAX Oscillator Duty Cycle DOSC VLX Voltage Limit On (VLX “L”) side LX switch on Notes: (1) VIN = 1.8V, VSS = 0V, IOUT = 1mA, Topt = 25°C, and External Circuit of Typical Application (2) VIN = 3V, VSS = 0V, IOUT = 1mA, Topt = 25°C, and External Circuit of Typical Application www.richtek-ic.com.tw 4 DS9261B-03 September 2001 RT9261B Preliminary Typical Operating Charateristics Start-up/Hold-on Voltage vs. Output Current Output Voltage vs. Output Current Start-up/Hold-on Voltage Vstart/Vhold (V) 2.5 4.0 Output Voltage (V) 1.5 Vstart 1 Vhold 0.5 0 30 60 90 120 150 3.0 1.5V 1.0V 2.5 2.0 1.5 1.0 0.5 VOUT = 3.3V L = 47uH 0 VOUT = 3.3V L = 47uH 0.0 180 0 50 100 150 Output Current vs. Ripple Voltage Output Current vs. Ripple Voltage 300 90 2.5V 150 1.5V 100 VOUT = 3.3V 50 COUT = 20uF L = 47uH 1.0V 0 0 Ripple Voltage (mVp-p) 3.0V 200 50 100 150 3.0V 80 2.0V 250 2.0V 70 60 2.5V 50 40 30 20 1.5V VOUT = 3.3V 1.0V 10 COUT = 68uF L = 47uH 0 200 0 50 100 150 200 Output Current (mA) Output Current (mA) Efficiency vs. output Current Output Current vs. Ripple Voltage 90 25 3.0V 2.5V 80 20 70 2.5V 15 Efficiency (%) Ripple Voltage (mVp-p) 200 Output Current (mA) Output Current (mA) Ripple Voltage (mVp-p) 3.0V 2.5V 2.0V 3.5 2 3.0V 10 1.0V 5 0 0 COUT = 170uF L = 47uH 50 100 150 Output Current (mA) DS9261B-03 September 2001 1.5V 60 50 40 30 20 VOUT = 3.3V 2.0V 1.5V 2.0V 1.0V 200 VOUT = 3.3V L = 47uH 10 0 0 50 100 150 200 Output Current (mA) www.richtek-ic.com.tw 5 RT9261B Preliminary Start-up/Hold-on Voltage vs. Output Current Output Voltage vs. Output Current Start-up/Hold-on Voltage Vstart/Vhold (V) 2.5 4.0 3.0V 3.5 Output Voltage (V) 2 1.5 Vstart 1 Vhold 0.5 0 20 40 60 80 100 2.5 2.0 1.5 1.0 VOUT = 3.3V L = 100uH 0.0 0 120 50 Output Current vs. Ripple Voltage 80 200 2.5V 150 100 VOUT = 3.3V 50 0 50 100 150 2.5V 70 60 50 40 3.0V 30 20 2.0V 1.0V VOUT = 3.3V 10 COUT = 20uF L = 100uH 1.5V 1.0V 0 Ripple Voltage (mVp-p) 3.0V 250 Ripple Voltage (mVp-p) 200 90 2.0V 200 COUT = 68uF L = 100uH 1.5V 0 0 50 Output Current (mA) 100 150 200 Output Current (mA) Output Current vs. Ripple Voltage Efficiency vs. output Current 100 18 2.5V 16 2.0V 14 90 3.0V 3.0V 80 1.0V 70 Efficiency (%) Ripple Voltage (mVp-p) 150 Output Current vs. Ripple Voltage 300 1.0V 10 8 6 2.5V 2.0V 1.5V 60 50 40 30 4 1.5V 2 0 0 50 100 www.richtek-ic.com.tw VOUT = 3.3V 20 COUT = 170uF L = 100uH 10 150 Output Current (mA) 6 100 Output Current (mA) Output Current (mA) 12 2.5V 2.0V 1.0V 0.5 VOUT = 3.3V L = 100uH 0 1.5V 3.0 200 VOUT = 3.3V L = 100uH 0 0 50 100 150 200 Output Current (mA) DS9261B-03 September 2001 RT9261B Preliminary Package Information D A D1 H B C C1 e e 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 -- 4.242 -- 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 0.381 0.432 0.015 0.017 3-Lead SOT-89 Surface Mount DS9261B-03 September 2001 www.richtek-ic.com.tw 7 RT9261B Preliminary D C B b H A e Symbol L A1 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 0.102 0.254 0.004 0.010 L 0.356 0.610 0.014 0.024 SOT- 25 Surface Mount Package www.richtek-ic.com.tw 8 DS9261B-03 September 2001 Preliminary DS9261B-03 September 2001 RT9261B www.richtek-ic.com.tw 9 RT9261B Preliminary RICHTEK TECHNOLOGY CORP. RICHTEK TECHNOLOGY CORP. Headquarter Taipei Office (Marketing) 6F, No. 35, Hsintai Road, Chupei City 8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5510047 Fax: (8863)5537749 Tel: (8862)89191466 Fax: (8862)89191465 Email: [email protected] www.richtek-ic.com.tw 10 DS9261B-03 September 2001