AIC1642 3-Pin One-Cell Step-Up DC/DC Converter DESCRIPTION FEATURES l l l l l l l A Guaranteed Start-Up from less than 0.9 V. High Efficiency. Low Quiescent Current. Less Number of External Components needed. Low Ripple and Low Noise. Fixed Output Voltage: 2.7V, 3.0V, 3.3V, and 5V. Space Saving Packages: SOT-89 and TO-92 The AIC1642 is a high efficiency step-up DC/DC converter for applications using 1 to 4 battery cells. Only three external components are required to deliver a fixed output voltage of 2.7V, 3.0V, 3.3V, or 5V. The AIC1642 starts up from less than 0.9V input with 1mA load. Pulse Frequency Modulation scheme brings optimized performance for applications with light output loading and low input voltages. The output ripple and noise are lower compared with the circuits operating in PSM mode. APPLICATIONS l l l l l l Pagers. Cameras. Wireless Microphones. Pocket Organizers. Battery Backup Suppliers. Portable Instruments. The PFM control circuit operating in 100KHz (max.) switching rate results in smaller passive components. The space saving SOT-89 and TO-92 packages make the AIC1642 is an ideal choice of DC/DC converter for space conscious applications, like pagers, electronic cameras, and wireless microphones. TYPICAL APPLICATION CIRCUIT VIN L1 100H + C2 22F SW VOUT D1 GS SS12 AIC1642-27 AIC1642-30 AIC1642-33 AIC1642-50 VOUT + C1 47F GND One Cell Step-Up DC/DC Converter Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw DS-1642-01 012102 1 AIC1642 ORDERING INFORMATION AIC1642-XXCXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL TB: TUBE BG: BAG SOT-89 TOP VIEW 1: GND 2: VOUT 3: SW PACKAGE TYPE X: SOT-89 Z: TO-92 1 OUTPUT VOLTAGE 27: 2.7V 30: 3.0V 33: 3.3V 50: 5.0V 3 1 TO-92 TOP VIEW 1: GND 2: VOUT 3: SW Example: AIC1642-27COTR 2 2 3 a 2.7V Version, in MSOP8 Package & Tape & Reel Packing Type ABSOLUATE MAXIMUM RATINGS Supply Voltage ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .12V SW pin Voltage ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .12V SW pin Switch Current ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 0.6A Operating Temperature Range ... ... ... ... ... ... ... ... ... ... ... ... ..... ... ... ... ... .... .--40C to 85C Storage Temperature Range ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... -65C to 150 C Lead Temperature (Soldering 10 Sec.) ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 260C TEST CIRCUIT AIC1642 100 2.5V VOUT SW FOUT GND Oscillator Test Circuit 2 AIC1642 n ELECTRICAL CHARACTERISTICS (TA=25C, IOUT=10mA, Unless otherwise specified) PARAMETER TEST CONDITIONS SYMBOL VIN=1.8V, AIC1642-27 Output Voltage VIN=1.8V, AIC1642-30 VIN=2.0V, AIC1642-33 VOUT VIN=3.0V, AIC1642-50 Input Voltage TYP. MAX. 2.633 2.700 2.767 2.925 3.000 3.075 3.218 3.300 3.382 4.875 5.000 5.125 VIN Start-Up Voltage IOUT=1mA, VIN:02V VSTART Hold-on Voltage IOUT=1mA, VIN:20V VHOLD No-Load Input Current IOUT=0mA Supply Current MIN. 0.8 AIC1642-27 42 AIC1642-30 50 AIC1642-33 60 AIC1642-50 V 8 V 0.9 V 0.7 V A 15 IIN UNIT IDD1 90 A IDD2 8 A VIN=VOUT x 0.95 Measurement of the IC input current (VOUT pin) VIN=VOUT + 0.5V Supply Current Measurement of the IC input current (VOUT pin) SW Leakage Current VSW =10V, VIN=VOUT + 0.5V SW Switch-On Resistance 0.5 AIC1642-27 2.2 AIC1642-30 2.1 AIC1642-33 2.0 RON AIC1642-50 A 1.9 VIN=VSW x 0.95, VSW =0.4V VIN=VOUT x 0.95 Oscillator Duty Cycle Measurement of the SW Pin Waveform DUTY 65 75 85 % FOSC 80 105 130 KHz VIN=VOUT x 0.95 Max. Oscillator Freq. Efficiency Measurement of the SW Pin Waveform 80 % 3 AIC1642 TYPICAL PERFORMANCE CHARACTERISTICS Capacitor (C1) : 47 F (Tantalum Type) Diode (D1) : 1N5819 Schottky Type 85 2.8 80 VIN=2.0V 2.6 75 Efficiency (%) Output voltage (V) 2.7 VIN=1.8V VIN=1.5V VIN=1.2V 2.5 VIN=2.0V 70 VIN=1.8V VIN=1.5V 65 2.4 VIN=1.2V 60 VIN=0.9V 2.3 VIN=0.9V 55 2.2 0 20 40 60 80 100 120 140 160 180 0 20 40 60 80 100 120 140 160 Output Current (mA) Output current (mA) Fig. 1 AIC1642-27 Load Regulation (L=100H CD54) Fig. 2 AIC1642-27 Efficiency (L=100H CD54) 1.0 180 2.78 0.9 2.76 Start up 0.7 Output Voltage VOUT (V) Input Voltage (V) 0.8 0.6 0.5 Hold on 0.4 0.3 0.2 2.74 No Load 2.72 2.70 2.68 2.66 2.64 0.1 0.0 0 Fig. 3 2 4 6 8 10 12 14 16 18 2.62 -40 160 82 140 80 120 100 80 60 40 -20 0 20 40 60 80 100 Temperature (C) Fig. 4 AIC1642-27 Output Voltage vs. Temperature Output Current (mA) AIC1642-27 Start-up & Hold-on Voltage (L=100H) Maximum Duty Cycle (%) Switching Frequency (kHz) n 78 76 74 72 70 68 20 -40 -20 Fig. 5 Temperature (C) AIC1642-27 Switching Frequency vs. Temperature 0 20 40 60 80 100 66 -40 Fig. 6 -20 0 20 40 60 80 100 Temperature (C) AIC1642-27 Maximum Duty Cycle vs. Temperature 4 AIC1642 3.2 52 2.8 48 Supply Current IDD1 (A) SW Turn On Resistance () TYPICAL PERFORMANCE CHARACTERISTICS 2.4 2.0 1.6 1.2 0.8 0.4 (Continued) 44 40 36 32 28 24 0.0 -40 -20 Fig. 7 0 20 40 60 80 20 -40 100 Temperature (C) AIC1642-27 SW On Resistance vs. Temperature -20 0 20 40 60 80 100 Temperature (C) AIC1642-27 Supply Current IDD1 vs. Temperature Fig. 8 85 3.1 3.0 VIN=2.0V 80 2.8 VIN=.8V VIN=1.5V 75 Efficiency (%) Output voltage VOUT(V) 2.9 2.7 2.6 2.5 2.4 VIN=1.2V 2.3 VIN=2.0V 70 VIN=1.8V 65 VIN=1.5V 60 2.2 2.0 0 10 20 30 40 VIN=1.2V 55 VIN=0.9 2.1 VIN=0.9V 50 60 70 80 90 50 100 110 120 130 140 0 Output Current (mA) Fig. 9 AIC1642-30 Load Regulation (L=100H CD54) 20 Fig. 10 1.0 40 60 80 100 120 140 160 180 Output Current (mA) AIC1642-30 Efficiency (L=100H CD54) 3.06 0.9 Start up 3.04 Output Voltage Vout (V) 0.8 Input Voltage (V) n 0.7 0.6 0.5 Hold on 0.4 0.3 0.2 0.1 0.0 No Load 3.02 3.00 2.98 2.96 2.94 2.92 0 2 4 6 8 10 12 14 16 18 20 Output Current (mA) Fig. 11 AIC1642-30 Start-up & Hold-on Voltage (L=100H) 2.90 -40 -20 0 20 40 60 80 100 Temperature (C) Fig. 12 AIC1642-30 Output Voltage vs. Temperature 5 AIC1642 160 82 140 80 Maximum Duty Cycle (%) Switching Frequency (kHz) TYPICAL PERFORMANCE CHARACTERISTICS 120 100 80 60 40 20 -20 0 20 40 60 80 78 76 74 72 70 66 -40 100 Temperature (C) Fig. 13 AIC1642-30 Switching Frequency vs. Temperature 3.2 52 2.8 48 2.4 2.0 1.6 1.2 0.8 -20 0 20 40 60 80 100 Temperature (C) Fig. 14 AIC1642-30 Maximum Duty Cycle vs. Temperature Supply Current IDD1 (A) SW Turn On Resistance () (Continued) 68 0 -40 44 40 36 32 28 24 0.4 0.0 -40 -20 0 20 40 60 80 100 20-40 -20 0 20 40 60 80 100 Temperature (C) Fig. 16 AIC1642-30 Supply Current vs. Temperature Temperature (C) Fig. 15 AIC1642-30 SW On Resistance vs. Temperature 90 3.4 3.3 85 VIN=2.0V 3.2 3.1 VIN=1.5V 80 VIN=1.8 Efficiency (%) Output Voltage (V) n 3.0 VIN=1.2 2.9 2.8 2.7 2.6 VIN=2.0V 75 70 VIN=1.8V VIN=1.5V 65 VIN=1.2V 60 2.5 2.4 55 VIN=0.9 2.3 VIN=0.9V 50 0 25 50 75 100 125 150 175 200 Output Current (mA) Fig. 17 AIC1642-33 Load Regulation (L=100H CD54) 0 25 50 75 100 125 150 175 200 Output Current (mA) Fig. 18 AIC1642-33 Efficiency (L=100H CD54) 6 AIC1642 TYPICAL PERFORMANCE CHARACTERISTICS 1.1 3.45 0.9 Output Voltage VOUT (V) Start up Input Voltage (V) 0.8 0.7 0.6 0.5 0.4 0.3 Hold on 3.40 3.30 3.25 3.20 3.15 3.10 0.1 3.05 0 Fig. 19 2 4 6 8 10 12 14 16 18 20 No Load 3.35 0.2 0.0 3.00 -40 -20 0 20 40 60 80 100 Temperature (C) Fig. 20 AIC1642-33 Output Voltage vs. Temperature Output Current (mA) AIC1642-33 Start-up & Hold-on Voltage (L=100H) 150 82 Maximum Duty Cycle (%) 140 Switching Frequency (KHz) (Continued) 3.50 1.0 130 120 110 100 90 80 70 80 78 76 74 72 70 68 60 50 -40 -20 0 20 40 60 80 66 -40 100 -20 0 20 40 60 80 100 Temperature (C) Fig. 21 AIC1642-33 Switching Frequency vs. Temperature Temperature (C) Fig. 22 AIC1642-33 Maximum Duty Cycle vs. Temperature 3.2 60 2.8 56 Supply Current IDD1 (A) SW Turn On Resistance () n 2.4 2.0 1.6 1.2 0.8 0.4 52 48 44 40 36 32 28 0.0 -40 -20 Fig. 23 0 20 40 60 80 100 Temperature (C) AIC1642-33 SW On Resistance vs. Temperature 24 -40 -20 0 20 40 60 80 100 Temperature (C) Fig. 24 AIC1642-33 Supply Current vs. Temperature 7 AIC1642 TYPICAL PERFORMANCE CHARACTERISTICS 5.5 85 VIN=3.0V 4.5 80 VIN=2.0V Efficiency (%) Output Voltage (V) (Continued) 90 5.0 4.0 VIN=1.5V 3.5 3.0 VIN=1.2V 75 VIN=3.0V 70 VIN=2.0V 65 VIN=1.5V 60 VIN=0.9V 2.5 55 VIN=0.9 2.0 VIN=1.2 50 1.5 0 50 100 150 200 250 300 350 45 400 0 50 100 150 Output Current (mA) Fig. 25 AIC1642-50 Load Regulation ( L=100H CD54) 5.3 1.6 5.2 Output Voltage Vout (V) Input Voltage (V) Fig. 26 1.8 1.2 Start up 1.0 0.8 0.6 Hold on 0.4 200 250 300 350 400 Output Current (mA) 1.4 0.2 AIC1642-50 Efficiency (L=100H, CD54) No Load 5.1 5.0 4.9 4.8 4.7 4.6 4.5 0.0 0 2 Fig. 27 4 6 8 10 12 14 16 18 4.4 -40 20 Output Current (mA) AIC1642-50 Start-up & Hold-on Voltage (L=100H) 150 82 140 80 130 120 110 100 90 80 70 60 -40 -20 20 40 60 80 100 78 76 74 72 70 68 66 -20 0 20 40 60 80 100 64 -40 Temperature (C) Fig. 29 0 Temperature (C) Fig. 28 AIC1642-50 Output Voltage vs. Temperature Maximum Duty Cycle (%) Switching Frequency (KHz) n AIC1642-50 Switching Frequency vs. Temperature -20 0 20 40 60 80 100 Temperature (C) Fig. 30 AIC1642-50 Maximum Duty Cycle vs. Temperature 8 AIC1642 TYPICAL PERFORMANCE CHARACTERISTICS 3.2 100 2.8 90 Supply Current IDD1 (A) SW Turn On Resistance () n 2.4 2.0 1.6 1.2 0.8 0.4 (Continued) 80 70 60 50 40 30 20 0.0 -40 -20 0 20 40 60 80 100 Temperature (C) Fig. 31 AIC1642-50 SW On Resistance vs. Temperature 10 -40 -20 0 20 40 60 80 100 Temperature (C) Fig. 34 AIC1642-50 Supply Current vs. Temperature BLOCK DIAGRAM SW 1.25V REF. VOUT 1M + Enable GND OSC, 100KHz PIN DESCRIPTIONS PIN1 : GND - Ground. Must be low impedance; sorer directly to ground plane. PIN3 : SW - Internal drain of N-MOSFET switch. PIN2 : VOUT - IC supply pin. Connect VOUT to the regulator output. 9 AIC1642 APPLICATION INFORMATION GENERAL DESCRIPTION AIC1642 PFM (pulse frequency modulation) control- tinuous conduction mode. Continuous conduction mode means that the inductor current does not ramp to zero during each cycle. ler ICs combine a switch mode regulator, N-channel power MOSFET, precision voltage reference, and VIN voltage detector in a single monolithic device. They IIN offer extreme low quiescient current, high efficiency, ID and very low gate threshold voltage to ensure start- IOUT SW up with low battery voltage (0.8V typ.). Designed to VOUT + maximize battery life in portable products, and minimize switching losses by only switching as EXT Isw Ico needed service the load. PFM controllers transfer a discrete amount of energy per cycle and regulate the output voltage by VEXT modulating switching frequency with the constant turn-on time. Switching frequency depends on load, input voltage, and inductor value, and it can range up to 100KHz. The SW on-resistance is typically 1.9 IIN IPK to 2.2 to minimize switch losses. When the output voltage drops, the error comparator enables 100kHz oscillator that turns on the ISW MOSFET around 7.5us and 2.5us off time. Turning on the MOSFET allows inductor current to ramp up, storing energy in a magnetic field. When MOSFET turns off that force inductor current through diode to Charge Co. ID IOUT the output capacitor and load. As the stored energy is depleted, the current ramp down until the diode VSW TDIS Discharge Co. turns off. At this point, inductor may ring due to residual energy and stray capacitance. The output cat pacitor stores charge when current flowing through the diode is high, and release it when current is low, Discontinuous Conduction Mode 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 ensure adequate time for energy transfer to output during the second half each cycle. Depending on circuit, PFM controller can operate in either discontinuous mode or con- 10 AIC1642 In the continuous mode, the switching frequency is VEXT 1 (VOUT + VD - VIN ) TON (VOUT + VD - VSW ) x VIN - VSW * [1 + ( )] 2 VOUT + VD - VSW 1 VOUT + VD - VIN TON VOUT + VD - VSW fSW = IIN IPK ISW where Vsw = switch drop and proportion to output current. ID IOUT Inductor Selection To operate as an efficient energy transfer element, the inductor must fulfill three require- VSW ments. First, the inductance must be low enough for the inductor to store adequate ent ergy under the worst case condition of minimum input voltage and switch ON time. Second, the inductance must also be high enough so maxi- Continuous Conduction Mode mum current rating of AIC1642 and inductor are not exceed at the other worst case condition of maximum input voltage and ON time. Lastly, the Continuous Conduction Mode inductor must have sufficiently low DC resis- At the boundary between continuous and dis- tance so excessive power is not lost as heat in continuous mode, output current (IOB) is deter- the windings. But unfortunately this is inversely related to physical size. mined by Minimum and maximum input voltage, output VIN 1 VIN IOB = * TON * (1 - x ) * * VOUT 2 L voltage and output current must be established in advance and then inductor can be selected. In discontinuous mode operation, at the end of where Vd is the diode drop, the switch ON time, peak current and energy in TON x = (RON + RS ) * L the inductor build according to RON= Switch turn on resistance, RS= Inductor DC resistance TON = Switch ON time In the discontinuous mode, the switching frequency (Fsw) is Fsw = 2 * (L) * (VOUT + VD - VIN) * (IOUT) VIN 2 x TON 2 (1 + x ) RON + Rs VIN IPK = * TON) * 1 - exp( - L RON + Rs x VIN * (TON ) * 1 - 2 L VIN TON L (simple loss equation), where x = (RON + RS ) * TON L 11 AIC1642 EL = VOUT+ VD - VSW x VIN- VSW x IPK = - * IOUT+ * TON * 1- V IN - V SW 2 2L 2 1 L x Ipk 2 2 Power required from the inductor per cycle must be equal or greater than PL/fSW = (VOUT + VD - VIN) * (IOUT) * ( Valley current (Iv) is VOUT+ VD - VSW x VIN - VSW x IV = - * IOUT- * TON* 1- 2 2L VIN - VSW 2 1 ) fsw In order for the converter to regulate the output. When loading is over IOB, PFM controller operates in continuous mode. Inductor peak current can be derived from Table 1 Indicates resistance and height for each coil. Power Inductor Type Coilcraft SMT Type DS1608 (www.coilcraft.com) DO3316 Sumida SMT Type CD54 Hold SMT Type PM54 Hold SMT Type PM75 Inductance ( H ) Resistance ( ) Rated Current Height (A) (mm) 22 0.10 0.7 47 0.18 0.5 100 0.38 0.3 22 0.08 2.7 47 0.14 1.8 47 0.25 0.7 100 0.50 0.5 47 0.25 0.7 100 0.50 0.5 33 0.11 1.2 Capacitor Selection 2.9 5.2 4.5 4.5 5.0 Most of the input supply is supplied by the input A poor choice for an output capacitor can result in bypass capacitor, the capacitor voltage rating poor efficiency and high output ripple. Ordinary should be at least 1.25 times greater than a aluminum electrolytic, while inexpensive may maximum input voltage. have unacceptably poor ESR and ESL. There are low ESR aluminum capacitors for switch mode DC-DC converters which work much well than general unit. Tantalum capacitors provide still better performance at more expensive. OS-CON capacitors have extremely low ESR in a small size. If capacitance is reduced, output ripple will increase. Diode Selection Speed, forward drop, and leakage current are the three main considerations in selecting a rectifier diode. Best performance is obtained with Schottky rectifier diode such 1N5819. Motorola makes MBR0530 in surface mount. For lower output power a 1N4148 can be used although efficiency and start-up voltage will suffer substantially. 12 AIC1642 VD = Diode drop. Component Power Dissipation The power dissipated in a switch loss is Operating in discontinuous mode, power loss in PDSW = the winding resistance of inductor can be ap- 2 TON VOUT + VD - VIN * (RON) * * (POUT ) 3 L VOUT proximate equal to PD L = 2 TON VOUT + VF * (RD ) * * (POUT ) 3 L VOUT The power dissipated in rectifier diode is VD PDd = * (POUT ) VOUT where POUT=VOUT * IOUT; RS=Inductor DC R; PHYSICAL DIMENSIONS l SOT-89 (unit: mm) D A SYMBOL MIN MAX C A 1.40 1.60 B 0.36 0.48 C 0.35 0.44 D 4.40 4.60 D1 1.62 1.83 E 2.29 2.60 D1 H E L B e e1 l e 1.50 (TYP.) e1 3.00 (TYP.) H 3.94 4.25 L 0.89 1.20 SOT-89 MARKING Part No. Marking AIC1642-27 AM27 AIC1642-30 AM30 AIC1642-33 AM33 AIC1642-50 AM50 13 AIC1642 l TO-92 (unit: mm) A E L C SYMBOL MIN MAX A 4.32 5.33 C e1 D 0.38 (TYP.) D 4.40 5.20 E 3.17 4.20 e1 1.27 (TYP.) 14