SS6639-50CZTR

SS6639 1-Cell, 3-Pin, Step-Up DC/DC Controller n FEATURES • • • • • • • • Guaranteed start-up from less than 0.9 V. High efficiency. Low quiescent current. Fewer external components needed. Low ripple and low noise. Fixed output voltage: 2.7, 3.0V, 3.3V, and 5V. Driver for external transistor. Space-saving package: SOT-89 and TO-92. n GENERAL DESCRIPTION The SS6639 is a high efficiency step-up DC/DC controller for applications using 1 to 4 battery cells. Only three external components are required to deliver a fixed output voltage of 2.7, 3.0V, 3.3V, or 5V. The SS6639 starts up from less than 0.9V input with a 1mA load. The Pulse Frequency Modulation scheme offers optimized performance for applications with light output loading and low input voltages. The output ripple and noise are lower than with circuits operating in PSM mode. n APPLICATIONS • • • • • • Pagers. Cameras. Wireless Microphones. Pocket Organizers. Battery Backup Suppliers. Portable Instruments. The PFM control circuit operating up to 100 KHz switching rate results in smaller passive components. The space-saving SOT-89 and TO-92 packages make the SS6639 an ideal choice of DC/DC controller for space-conscious applications, such as pagers, electronic cameras, and wireless microphones. Using an external transistor driver pin (EXT), the SS6639 is recommended for applications requiring currents from several tens to several hundreds of milliamperes. n TYPICAL APPLICATION CIRCUIT VIN D1 VOUT L1 33µH R1 + C1 47µF GS SS14 SS6639-27 SS6639-30 EXT SS6639-33 SS6639-50 GND VOUT *Q1 2SD1803 300 + C3 100µF C2 10nF *Q1: Sanyo 25D1803S-TC 60V/5A/20W 100mA Load Current Step-Up Converter Rev.2.01 6/26/2003 www.SiliconStandard.com 1 of 12 SS6639 n ORDERING INFORMATION SS6639-XXCXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL BG: BAG PACKAGE TYPE X: SOT-89 Z: TO-92 OUTPUT VOLTAGE 27: 2.7V 30: 3.0V 33: 3.3V 50: 5.0V EX: SS6639-27CXTR à 2.7V Version, in SOT-89 Package in Tape and Reel Packing SOT-89 TOP VIEW 1: GND 2: VOUT 3: EXT 1 2 3 TO-92 TOP VIEW 1: GND 2: VOUT 3: EXT 1 2 3 n ABSOLUTE MAXIMUM RATINGS Supply Voltage (VOUT Pin) ……………….………………………………………………….12V EXT pin Voltage ……………………………………………………..……….-0.3V to Vout+0.3V EXT pin Current …………………………………………………..……………………….± 50mA Operating Temperature Range ………………………………..……………….-40°C to 85°C Storage Temperature Range ……………………………………..…………… -65°C to 150 °C Lead Temperature (Soldering 10 Sec.) ………………………..…………………………260°C n TEST CIRCUIT SS6639 2.5V VOUT GND EXT FOUT Oscillator Test Circuit Rev.2.01 6/26/2003 www.SiliconStandard.com 2 of 12 SS6639 n ELECTRICAL CHARACTERISTICS (TA=25°C, IO=10mA, unless otherwise specified) PARAMETER TEST CONDITIONS SS6639-27 SS6639-30 SS6639-33 SS6639-50 VIN=1.8V VIN=1.8V VIN=2.0V VIN=3.0V SYMBOL MIN. 2.633 2.925 3.218 4.875 TYP. 2.700 3.000 3.300 5.000 MAX. 2.767 3.075 3.382 5.125 8 UNIT Output Voltage VOUT V Input Voltage Start-Up Voltage Hold-on Voltage No-Load Input Current IOUT=1mA, VIN:0→2V IOUT=1mA, VIN:2→0V IOUT=0mA SS6639-27 SS6639-30 SS6639-33 SS6639-50 EXT at no load, VIN=VOUT x 0.95 Measurement of the IC input current (VOUT Pin) SS6639-27 SS6639-30 SS6639-33 SS6639-50 EXT at no load, VIN=VOUT + 0.95 Measurement of the IC input current (VOUT Pin) SS6639-27 SS6639-30 SS6639-33 SS6639-50 VEXT=VOUT – 0.4V SS6639-27 SS6639-30 SS6639-33 SS6639-50 VEXT= 0.4V VIN VSTART VHOLD IIN 0.6 18 45 50 60 80 0.8 V V V µA µA 0.9 IDD1 Supply Current 1 IDD2 Supply Current 2 7 7 7 7 µA EXT “H” On-Resistance REXTH 300 200 185 130 110 80 70 60 Ω EXT “L” On-Resistance REXTL Ω Rev.2.01 6/26/2003 www.SiliconStandard.com 3 of 12 SS6639 n ELECTRICAL CHARACTERISTICS PARAMETER Oscillator Duty Cycle (Continued) TEST CONDITIONS VIN=VOUT x 0.95 Measurement of the EXT Pin Waveform VIN=VOUT x 0.95 SYMBOL MIN. 65 TYP. 75 MAX. 85 UNIT % DUTY Max. Oscillator Freq. Efficiency Measurement of the EXT Pin Waveform FOSC η 80 105 80 130 KHz % n TYPICAL PERFORMANCE CHARACTERISTICS Inductor (L1): 33µH (Pin Type) Diode 2.80 2.75 Capacitor (C1): 47µF (Tantalum Type) Transistor (Q1): 2SD1803 90 85 (D1): 1N5819 Schottky Type Output Voltage (V) 2.70 2.65 2.60 2.55 2.50 2.45 2.40 0 Efficiency (%) V I N = 2.0 V V I N = 1.8V V IN = 1.2 V V I N = 1.5 V 80 75 V I N = 2.0V V IN = 1.8V 70 65 60 V I N = 1.5V V I N = 1.2V V IN = 0 .9V V I N =0.9V 50 100 150 200 250 300 350 400 450 500 55 50 0 50 100 150 200 250 300 350 400 450 500 Output Current (mA) Fig. 1 SS6639-27 Load Regulation (L=33µH) 3.1 3.0 90 Output Current (mA) Fig. 2 SS6639-27 Efficiency (L=33uH) VIN=2.0V 85 Output Voltage (V) VIN=2.0V Efficiency (%) 2.9 2.8 2.7 VIN=1.2V VIN=1.5V VIN=1.8V 80 VIN=1.8V 75 VIN=1.5V 70 VIN=0.9V 2.6 2.5 2.4 VIN=1.2V 65 VIN=0.9V 60 0 50 100 150 200 250 300 350 400 450 0 50 100 150 200 250 300 350 400 450 Output Current (mA) Fig. 3 SS6639-30 Load Regulation (L=33 µH) Output Current (mA) Fig. 4 SS6639-30 Efficiency (L=33µH) Rev.2.01 6/26/2003 www.SiliconStandard.com 4 of 12 SS6639 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 3.4 90 3.2 85 Output Voltage (V) 3.0 Efficiency (%) VIN=1.5V VIN=2.0V 80 75 VIN=2.0V 2.8 VIN=1.2V 2.6 70 VIN=1.5V 65 VIN=0.9V 0 50 100 150 200 250 300 350 400 2.4 60 0 50 100 150 200 250 300 350 400 Output Current (mA) Fig. 5 SS6639-33 Loading Regulation (L=33µH) 5.25 5.00 4.75 4.50 4.25 4.00 3.75 3.50 3.25 0 Output Current (mA) Fig. 6 SS6639-33 Efficiency (L=33 µH) 90 85 80 VIN=3.0V VIN=1.5V VIN=2.0V VIN=0.9V VIN=1.2V Output Voltage (V) VIN=2.0V V IN =1.5V Efficiency (%) 700 VIN=3.0V 75 70 65 60 55 50 45 VIN=0.9V VIN=1.2V 100 200 300 400 500 600 40 0 100 200 300 400 500 600 700 Output Current (mA) Fig. 7 SS6639-50 Load Regulation (L=33µH) 2.0 1.8 1.6 1.0 1.2 Output Current (mA) Fig. 8 SS6639-50 Efficiency (L=33µH) Output Voltage (V) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 20 40 60 80 100 120 140 160 180 200 Input Voltage (V) Start up 0.8 Start up 0.6 Hold on 0.4 Hold on 0.2 0.0 0 20 40 Output Current (mA) Fig. 9 SS6639-27 Start-up & Hold-on Voltage (L=33µH) Output Current (mA) 60 80 100 120 140 160 Fig. 10 SS6639-30 Start-up & Hold-on Voltage (L=33µH) Rev.2.01 6/26/2003 www.SiliconStandard.com 5 of 12 SS6639 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 1.2 1.6 Start up 1.0 1.4 1.2 Start up Input Voltage (V) 0.8 Input Voltage (V) 1.0 0.8 0.6 0.4 0.2 0.6 Hold on 0.4 Hold on 0.2 0.0 0 20 40 60 80 100 120 140 160 0.0 0 20 40 60 80 100 120 140 160 Output Current (mA) Fig. 11 SS6639-33 Start-up & Hold-on Voltage (L=33µH) Output Current (mA) Fig. 12 SS6639-50 Start-up & Hold-on Voltage (L=33uH) 1.2 1.6 Start up 1.0 1.4 1.2 Start up Input Voltage (V) 0.8 Input Voltage (V) 1.0 0.8 0.6 0.4 0.2 0.6 Hold on 0.4 Hold on 0.2 0.0 0 20 40 60 80 100 120 140 160 0.0 0 20 40 60 80 100 120 140 160 Output Current (mA) Fig. 13 SS6639-33 Start-up & Hold-on Voltage (L=33µH) 6.0 5.5 135 130 Output Current (mA) Fig. 14 SS6639-50 Start-up & Hold-on Voltage (L=33uH) VOUT =5.0V Switching Frequency (kHz) 125 120 115 110 105 100 95 90 Output Voltage (V) 5.0 4.5 4.0 3.5 3.0 2.5 2.0 -40 V OUT = 5.0V V OUT = 3.3V V OUT = 3.0V V OUT = 2.7V V OUT = 3.3V V OUT = 3.0V V OUT = 2.7V -20 0 20 40 60 80 100 85 -40 -20 0 20 40 60 80 100 Output Current (mA) Fig. 15 SS6639 Output Voltage vs. Temperature Output Current (mA) Fig. 16 SS6639 Switching Frequency vs.Temperature Rev.2.01 6/26/2003 www.SiliconStandard.com 6 of 12 SS6639 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 80 80 75 Maximum Duty Cycle (%) 78 77 76 75 74 73 72 71 70 -40 - 20 0 20 40 V OUT 2.7V V OUT 3.0V V OUT = = = Supply Current IDD1 (µA) 79 70 65 60 55 50 45 40 35 30 -40 -20 0 20 40 V OUT = 5.0V V OUT = 3.3V V OUT = 3.0V V OUT = 2.7V 60 80 100 60 80 100 Output Current (mA) Fig. 17 SS6639 Maximum Duty Cycle vs. Temperature Temperature (°C) Fig. 18 SS6639 Supply Current vs. Temperature 400 360 130 120 110 Resistance (O) 100 90 80 70 60 50 40 -40 Resistance (O) VOUT = VOUT = VOUT = VOUT = 2.7V 3.0V 3.3V 5.0V 320 280 240 200 160 120 80 VOUT = 2.7V VOUT = 3.0V VOUT = 3.3V VOUT = 5.0V -20 0 20 40 60 80 100 Temperature (°C) Fig. 19 SS6639 EXT "L" On-Resistance 40 -40 -20 0 20 40 60 80 100 Temperature (°C) Fig. 20 SS6639 EXT "H" On-Resistance n BLOCK DIAGRAM VOUT 1M + EXT 1.25V REF. Enable GND OSC, 100KHz Rev.2.01 6/26/2003 www.SiliconStandard.com 7 of 12 SS6639 n PIN DESCRIPTIONS Pin 1: GND: Ground. Must be low impedance; solder directly to ground plane. Pin 2: VOUT: IC supply pin. Connect Vout to the regular output. Pin 3: EXT: Push-pull driver output for external power. Switch. n APPLICATION INFORMATION General Description The SS6639 PFM (pulse frequency modulation) controller IC combines a switch mode regulator, a push-pull driver, a precision voltage reference, and a voltage detector in a single monolithic device. It offers extremely low quiescent current, high efficiency, and very low gate-threshold voltage to ensure start-up with low battery voltage (0.8V typ.). Designed to maximize battery life in portable products, it minimizes switching losses by only switching as needed to service the load. PFM controllers transfer a discrete amount of energy per cycle and regulate the output voltage by modulating the switching frequency with a constant turn-on time. Switching frequency depends on load, input voltage, and inductor value and can range up to 100 KHz. When the output voltage drops, the error comparator enables the 100 kHz oscillator which turns the MOSFET on for around 7.5us and off for 2.5µs. Turning on the MOSFET allows inductor current to ramp up, storing energy in the magnetic field. When the MOSFET turns off, the inductor forces current through the diode to the output capacitor and the load. As the stored energy is depleted, the current ramps down until the diode turns off. At this point, the inductor may ring due to residual energy and stray capacitance. The output capacitor stores charge when current flowing through the diode is high, and releases it when current is low, thereby maintaining a steady voltage across the load. As the load increases, the output capacitor discharges faster and the error comparator initiates cycles sooner, increasing the switching frequency. The maximum duty cycle ensures adequate time for energy transfer to the output during the second half of each cycle. Depending on the circuit, PFM controllers can operate in either discontinuous mode or continuous conduction mode. The continuous conduction mode means that the inductor current does not ramp to zero during each cycle. VIN IIN SW EXT Isw + Ico VOUT ID IOUT Discontinuous Conduction Mode Rev.2.01 6/26/2003 www.SiliconStandard.com 8 of 12 SS6639 At VEXT the boundary between continuous and discontinuous modes, the output current (IOB) is determined by IIN IPK VIN   1 VIN IOB =  * TON * (1 − x ) * *  VOUT + VD  2 L where VD is the diode drop, ISW X = (RON + RS) ∗ TON L RON= Switch turn on resistance, RS= Inductor DC resistance Charge Co. ID TDIS Discharge Co. IOUT TON = Switch ON time In the discontinuous mode, the switching frequency VSW (Fsw) is FSW = t 2(L) * (VOUT + VD − VIN) * (IOUT) VIN 2 * TON 2 * (1 + x ) In the continuous mode, the switching frequency is fsw = Discontinuous Conduction Mode VEXT (VOUT + VD − VIN ) 1 * TON (VOUT + VD − VSW ) x VIN − VSW * [1 + ( )] 2 VOUT + VD − VSW 1  VOUT + VD − VIN  ≅ *  TON  VOUT + VD − VSW  where Vsw = switch drop and is proportional to IIN IPK output current. ISW ID IOUT VSW t Continuous Conduction Mode INDUCTOR SELECTION To operate as an efficient energy transfer element, the inductor must fulfill three requirements. First, the inductance must be low enough for the inductor to store adequate energy under the worst case condition of minimum input voltage and switch ON time. Second, the inductance must also be high enough so the maximum current rating of the SS6639 and the inductor are not exceeded at the other worst case condition of maximum input voltage and ON time. Lastly, the inductor must have sufficiently low DC resistance so excessive power is not lost as heat in the windings. Unfortunately this is inversely related to physical size. Rev.2.01 6/26/2003 www.SiliconStandard.com 9 of 12 SS6639 Minimum and maximum input voltage, output voltage and output current must be established before an inductor can be selected. In discontinuous mode operation, at the end of the switch ON time, peak current and energy in the inductor build according to RON + RS   VIN   IPK =  * TON)   * 1 − exp(− L   RON + RS   x  VIN   ≅  * ( TON) * 1 −  L 2   ≅ VIN * TON L Power required from the inductor per cycle must be equal to, or greater than PL 1 = (VOUT + VD − VIN) * (IOUT) * ( ) fSW fsw in order for the converter to regulate the output. When the loading exceeds IOB, the PFM controller operates in continuous mode. Inductor peak current can be derived from  VOUT + VD − VSW x  IPK =  − VIN − VSW 2  x  VIN − VSW   * IOUT +   * TON * 1 −  2L 2    (simple lossless equation), where X = (RON + RS) ∗ EL = 1 L * IPK 2 2 TON L Valley current (Iv) is  VOUT + VD − VSW x  IV =  −  * IOUT VIN − VSW 2  x  VIN − VDE   *  * T ON * 1 −  2L 2    Table 1 Indicates resistance and height for each coil. Power Inductor Type Sumida SMT Type CD54 Hold SMT Type PM54 Hold SMT Type PM75 Huan Feng PIN Type V0810 Inductance ( µH ) Resistance ( Ω ) Rated Current (A) height (mm) 47 100 47 100 33 33 0.25 0.50 0.25 0.50 0.11 40m 0.7 0.5 0.7 0.5 1.2 2 4.5 4.5 5.0 10.0 CAPACITOR SELECTION A poor choice for an output capacitor can result in poor efficiency and high output ripple. Ordinary aluminum electrolytic capacitors, while inexpensive, may have unacceptably poor ESR and ESL. There are low ESR aluminum capacitors for switch mode DC-DC converters which work much better than general-purpose components. Tantalum capacitors provide still better performance but are more expensive. OS-CON capacitors have extremely low ESR in a small size. If the capacitance is reduced, the Rev.2.01 6/26/2003 output ripple will increase. As most of the input supply is applied across the input bypass capacitor, the capacitor voltage rating should be at least 1.25 times greater than the maximum input voltage. DIODE SELECTION Speed, forward drop, and leakage current are three main considerations in selecting a rectifier diode. The best performance is obtained with a Schottky rectifier www.SiliconStandard.com 10 of 12 SS6639 diode such as the 1N5819. Motorola makes the MBR0530 for surface mount. For lower output power a 1N4148 can be used although efficiency and start-up voltage will suffer substantially. COMPONENT POWER DISSIPATION Operating in discontinuous mode, the power loss in the winding resistance of the inductor is approximately equal to PDL = 2  TON   VOUT + VD  *  * (RS ) *   * (POUT ) 3 L  VOUT  where POUT=VOUT * IOUT ; RS=Inductor DC R; VD = Diode drop. The power dissipated in switching losses is PDsw = 2 3  TON  *  * (RON ) * (IOUT ) * (POUT ) L The power dissipated in the rectifier diode is  VD  PDD =   * (POUT )  VOUT  Rev.2.01 6/26/2003 www.SiliconStandard.com 11 of 12 SS6639 n PHYSICAL DIMENSIONS • SOT-89 (unit: mm) D D1 C A SYMBOL A B C D MIN 1.40 0.36 0.35 4.40 1.62 2.29 MAX 1.60 0.48 0.44 4.60 1.83 2.60 1.50 (TYP.) 3.00 (TYP.) H E D1 E e L e e1 B e1 H L 3.94 0.89 4.25 1.20 l SOT-89 MARKING Marking AU27 AU30 AU33 AU50 Part No. SS6639-27 SS6639-30 SS6639-33 SS6639-50 • TO-92 (unit: mm) A L C E SYMBOL A C MIN 4.32 MAX 5.33 0.38 (TYP.) e1 D D E e1 L 4.40 3.17 5.20 4.20 1.27 (TYP.) 12.7 - Information furnished by Silicon Standard Corporation is believed to be accurate and reliable. However, Silicon Standard Corporation makes no guarantee or warranty, express or implied, as to the reliability, accuracy, timeliness or completeness of such information and assumes no responsibility for its use, or for infringement of any patent or other intellectual property rights of third parties that may result from its use. Silicon Standard reserves the right to make changes as it deems necessary to any products described herein for any reason, including without limitation enhancement in reliability, functionality or design. No license is granted, whether expressly or by implication, in relation to the use of any products described herein or to the use of any information provided herein, under any patent or other intellectual property rights of Silicon Standard Corporation or any third parties. Rev.2.01 6/26/2003 www.SiliconStandard.com 12 of 12