SP6680 ® High Efficiency Buck/Boost Charge Pump Regulator ■ Ideal For Sim Card Applications In Cellular Phones ■ Low Profile, Inductorless Regulator ■ Up To 96% Power Efficiency ■ +2.7V to +6.3V Input Voltage Range ■ 5.8V Output Voltage ■ 60mA Output Current ■ 75µA Quiescent Current ■ 4µA Shutdown Current ■ External 32.768kHz Clock Input ■ Three Programmable Charge Pump Frequencies: 8.192kHz, 32.768kHz, and 262.14kHz ■ Internal Oscillator At 16.7kHz, When CLK Pin Is Held High ■ Space Saving 10-Pin µSOIC Package VOUT 1 10 CF2P CF1P 2 SP6680 9 CF1N 8 GND VIN 3 10 Pin MSOP C/4 4 7 CF2N 6 CLK CX8 5 Now Available in Lead Free Packaging DESCRIPTION The SP6680 is a charge pump ideal for converting a +3.6V Li-Ion battery input to a +5.0V regulated output. An input voltage range of +2.7V to +6.3V is converted to a regulated output of 5.8V. The SP6680 device will operate at three different switching frequencies corresponding to three different output resistances and load current ranges. An external 32.768kHz nominal clock signal is used to produce three synchronized pump frequencies through the use an internal phase look loop of an to drive the charge pump. Two control inputs can adjust the internal pump frequency on the fly to 8.192kHz (fINPUT / 4), 32.768kHz (fINPUT x 1), or 262.14kHz (fINPUT x 8). The charge pump configuration dynamically changes to optimize power efficiency. At low input voltages the charge pump doubles the input while at higher inputs the output is 1.5 times the input. The SP6680 can deliver high power efficiencies up to 96% with low quiescent currents from 75µA to 800µA. The SP6680 is offered in a 10-Pin µSOIC package. TYPICAL APPLICATION CIRCUIT 2.2µF 2.2µF CF1N CF1P 2 VIN CF2P 9 CF2N 10 7 3 1 VOUT = +5.8V SP6680 +3.6V Lithium-Ion Battery 4 5 6 8 SP6200 CMOS LDO VIN +5.0V output VOUT GND 4.7µF GND 2.2µF 2.2µF C/4 Cx8 CLK *All Capacitors Are Ceramic Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 1 © Copyright 2004 Sipex Corporation ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. VIN.........................................................-0.3V to +7.0V VOUT......................................................-0.3V to +7.0V IOUT....................................................................100mA Storage Temperature........................-65˚C to +150˚C Power Dissipation Per Package 10-pin mSOIC (derate 8.84mW/OC above +70OC)..................720mW Junction Temperature........................................125˚C ELECTRICAL CHARA CTERISTICS VIN = +2.7 to +6.3V, fCLK = 32.768kHz, CIN = 4.7µF (ceramic), CF1 = CF2 = COUT = 2.2µF, (ESR = 0.03 Ω) and TAMB = -40°C to +85°C unless otherwise noted. PARAMETER Supply Voltage, VIN MIN. TYP. MAX. UNITS 2.75 3.6 6.3 V 75 170 800 150 300 1500 µA fPUMP = fCLK/4 fCLK = fPUMP fPUMP = fCLK x 8 mA 2.7V<VIN<6.3V, Note 1 µA VIN = 4.2V, clock not present, -40˚ C to +70˚ C kHz Operational (supplied externally) Quiescent Current, IQ In-Rush Current into VIN, IINRUSH 500 Off Current, IOFF 4.4 Input Clock Frequency, fCLK 10 32.768 Pump Frequency, fPUMP (Note 2) 0 32.768 8.192 262.14 16.7 Input Threshold Voltage VIL VIH Hysteresis for Mode Transition Voltage Transient Response: Maximum Transient Amplitude Date: 5/25/04 3.55 3.55 VIN = 4.2V fCLK C/4pin input Cx8pin input no input present present present high X low high X low X low low high low 0.4 V Digital inputs = fCLK, fCLK/4, fCLK x 8 Digital inputs = fCLK, fCLK/4, fCLK x 8 0.1 1.0 10 10 µA Digital inputs = fCLK, fCLK/4, fCLK x 8 Digital inputs = fCLK, fCLK/4, fCLK x 8 3.70 3.70 3.85 3.85 1.3 Input Current IIN(low) IIN(high) Mode Transition Voltage, X1.5 to X2, VIN falling kHz CONDITIONS 50 V mVpp 1.5 1.5 1.5 % fpump = fCLK/4, ILOAD = 1mA fpump, fCLK, ILOAD = 5mA VIN rising to VIN falling ILOAD ∆t fPUMP 100µA to 2mA 2mA to 20mA 20mA to 60mA 5µs 5µs 5µs 8.192kHz 32.768kHz 262.14kHz SP6680 High Efficiency Buck/Boost Charge Pump Regulator 2 © Copyright 2004 Sipex Corporation ELECTRICAL CHARA CTERISTICS VIN = +2.7 to +6.3V, fCLK = 32.768kHz, CIN = 4.7µF (ceramic), CF1 = CF2 = COUT = 2.2µF, and TAMB = -40°C to +85°C unless otherwise noted. PARAMETER MIN. TYP. MAX. UNITS Output Resistance, ROUT 60 20 Ω 30 12.5 Average Output Voltage, VOUT 5.1 5.1 5.1 5.1 5.8 5.8 5.6 5.6 6.3 6.3 6.3 6.3 5.1 5.1 5.1 5.1 5.8 5.8 5.5 5.6 6.3 6.3 6.3 6.3 5.1 5.1 5.1 5.1 5.6 5.8 5.3 5.8 6.3 6.3 6.3 6.3 V Power Efficiency, PEFF 93 80 92 54 96 80 92 57 % 92 81 91 60 CONDITIONS VIN ILOAD fPUMP mode 3.85V 2mA 8.192kHz X2 3.85V 10mA 32.768kHz X2 3.85V 40mA 262.14kHz X2 VIN ILOAD fPUMP mode 3.0V 3.55V 3.85V 6.3V 2mA 2mA 2mA 2mA 8.192kHz 8.192kHz 8.192kHz 8.192kHz X2 X2 X1.5 X1.5 3.0V 3.55V 3.85V 6.3V 10mA 10mA 10mA 10mA 32.768kHz 32.768kHz 32.768kHz 32.768kHz X2 X2 X1.5 X1.5 3.0V 3.55V 3.85V 6.3V 40mA 40mA 40mA 40mA 262.14kHz 262.14kHz 262.14kHz 262.14kHz X2 X2 X1.5 X1.5 VIN ILOAD fPUMP mode 3.0V 3.55V 3.85V 6.3V 2mA 2mA 2mA 2mA 8.192kHz 8.192kHz 8.192kHz 8.192kHz X2 X2 X1.5 X1.5 3.0V 3.55V 3.85V 6.3V 10mA 10mA 10mA 10mA 32.768kHz 32.768kHz 32.768kHz 32.768kHz X2 X2 X1.5 X1.5 3.0V 3.55V 3.85V 6.3V 40mA 40mA 40mA 40mA 262.14kHz 262.14kHz 262.14kHz 262.14kHz X2 X2 X1.5 X1.5 Note 1: fCLK applied 10ms after VIN is present. Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 3 © Copyright 2004 Sipex Corporation PINOUT VOUT 1 CF1P 2 10 CF2P SP6680 8 GND VIN 3 C/4 4 9 CF1N 10 Pin MSOP 7 CF2N 6 CLK CX8 5 PIN ASSIGNMENTS Pin 6 — CLK — 32.768kHz Clock. Connect this input pin to an external 32.768kHz clock to drive the frequency of the charge pump. Logic low inputs on the C/4 and Cx8 pins sets the internal charge pump frequency according to Table 1. Shutdown mode for the device is set when there is no clock signal present on this input pin, or when it is pulled to ground. Pin 1— VOUT — Regulated charge pump output from +5.2V to +6.3V. The output voltage is regulated to 5.8V nominal output. Pin 2 — CF1P — Positive terminal to the charge pump flying capacitor, CF1. Pin 3 — VIN — Input pin for the +2.7V to +6.3V supply voltage. Pin 7 — CF2N — Negative terminal to the charge pump flying capacitor, CF2. Pin 4 — C/4 — This is a control line for the internal charge pump frequency. When this control line is forced to a logic high, the internal charge pump frequency is set to 1/4 of the CLK frequency, provided that Cx8 is low. Pin 8 — GND — Ground reference. Pin 9 — CF2P — Positive terminal to the charge pump flying capacitor, CF2. Pin 5 — Cx8 — This is a control line for the internal charge pump frequency. When this control line is forced to a logic high, the internal charge pump frequency is set to x8 of the CLK frequency. Date: 5/25/04 Pin 10 — CF1N — Negative terminal to the charge pump flying capacitor, CF2. SP6680 High Efficiency Buck/Boost Charge Pump Regulator 4 © Copyright 2004 Sipex Corporation DESCRIPTION THEORY OF OPERATION The SP6680 device is a regulated CMOS charge pump voltage converter that can be used to convert a +2.7V to +6.3V input voltage to a nominal +5.2V to +6.3V output. These devices are ideal for cellular phone designs involving battery-powered and/or board level voltage conversion applications. There are seven major circuit blocks for the SP6680 device. Refer to Figure 1. An external clock signal with a frequency of 32.768kHz nominal is required for device operation. A designer can set the SP6680 device to operate at 3 different charge pump frequencies: 8.192kHz (fINPUT / 4), 32.768kHz (fINPUT x 1), and 262.14kHz (fINPUT x 8). The three frequencies correspond to three nominal load current ranges: 2mA, 20mA, and 60mA, respectively. The SP6680 device optimizes for high power efficiency with a low quiescent current of 100µA at 8.198kHz, 200µA at 32.768kHz, and 1.0mA at 262.14kHz. When there is no external clock signal input, the device is in a low-power shutdown mode drawing 4.4µA (typical) current. 2) The Clock Manager accepts the digital input voltage levels (including the input clock) and translates them to VCC and 0V. It also determines if a clock is present in which case the device is powered up. If the CLK input is left floating or pulled near ground, the device shuts down and VIN is shorted to VOUT. The worst case digital low is 0.4V and the worst case digital high is 1.3V. This block contains a synthesizer that generates the internal pump clock which runs at the frequency controlled with the C/4 and Cx8 logic pins. 1) The Voltage Reference contains a band gap and other circuits that provide the proper current biases and voltage references used in the other blocks. 3) The Charge Pump Switch Configuration Control determines the pump configuration depending upon VIN as described earlier and programs the Clock Phase Control. For an input supply voltage from +2.7V to +3.7V, an X2 doubling architecture is enabled. This mode requires one flying capacitor and one output capacitor. For an input supply voltage greater than +3.7V up to +6.3V, an X1.5 multiplier architecture is enabled. This mode requires two flying capacitors and one output capacitor. The SP6680 device is ideal for designs using +3.6V lithium ion batteries such as cell phones, PDAs, medical instruments, and other portable equipment. For designs involving power sources above +2.7V up to +6.3V, the internal charge pump switch architecture dynamically selects an operational mode that optimizes efficiency. The SP6680 device regulates the maximum output voltage in steady state to +6.3V. VIN 3 Voltage Reference CLK Cx8 C/4 6 5 4 Charge Pump Switch Configuration Control SP6680 Charge Pump Switches Clock Manager Clock Phase Control Drivers VOUT Control 2 CF1P 9 CF1N 10 CF2P 7 CF2N 1 VOUT CF1 CF2 COUT 8 GND Figure 1. Internal Block Diagram of the SP6680 Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 5 © Copyright 2004 Sipex Corporation 4) The Clock Phase Control accepts the clock and mode control generated by the Clock Manager and the Charge Pump Switch Configuration Control. This block then provides several clock phases going to the Drivers block. If VIN is above 3.70V, the device is reconfigured and multiplies the input by a factor of 1.5. This mode reduces the current drawn from the supply and hence increases the power efficiency. If the output approaches 5.8V again, the charge transfer to the load capacitor is truncated. 5) The VOUT Control regulates the Clock Phase Control to ensure VOUT does not exceed +6.0V. APPLICATION INFORMATION 6) The Drivers block drives the clock phase information to the gates of the large pump transistors. Refer to Figure 3 for a typical SIM card application circuit with the SP6680. Oscillator Control 7) The Charge Pump Switch block contains the large transistors that transfer charge to the fly and load capacitors. The external clock frequency required to drive the internal charge pump oscillator is 32.768kHz (nominal) at the CLK pin. When there is no clock signal present at the CLK pin, the SP6680 device is in a low-power shutdown mode. In normal operation of the device VIN is connected between +2.7 and 6.3V. Refer to Figure 2 for a typical application circuit. When no clock is present (CLK is floating or near ground) the device is in shutdown and the output is connected to the input. This shutdown feature will work either in start up or after the device is pumping. Once a clock is present, the band gap is activated, but only if VIN > 2.3V. Otherwise the device remains in shutdown mode. Once the reference voltage is stable, the device begins the pumping operation. C/4 and Cx8 are two control lines for the internal charge pump oscillator. When the C/4 control line is forced to a logic high and the Cx8 control line is at a low, the internal charge pump oscillator is set to 8.192kHz. When both the C/4 and Cx8 control lines are at a logic low, the internal charge pump oscillator is set to the input clock signal, 32.768kHz. When the C/4 control line is forced to a logic high, the internal charge pump oscillator is set to 262.14kHz. If VIN < 3.70V, the device is configured as a doubler. However, if the output approaches 5.8V, the doubler action is truncated. CF1 = 2.2µF VOUT 1 CF1P COUT = 2.2µF VIN CF2P CF1N 9 2 SP6680 GND 3 8 C/4 4 Cx8 5 Frequency Control Inputs CIN = 4.7µF 10 7 6 CF2 = 2.2µF CF2N CLK Input Clock Figure 2. Typical Application for the SP6680 Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 6 © Copyright 2004 Sipex Corporation 2.2µF 2.2µF CF1N CF1P VIN CF2P 9 2 CF2N 10 7 3 1 LDO VOUT = +5.2V to +6.3V +5.0V output SP6680 +3.6V Lithium-Ion Battery 4 5 6 8 4.7µF 2.2µF GND 2.2µF C/4 Cx8 CLK Figure 3. Typical SIM Card Application Circuit for the SP6680 Any standard CMOS logic output is suitable for driving the C/4 or Cx8 control lines as long as logic low is less than 0.4V and logic high is greater than 1.3V. 100 SP6680 Efficiency vs Battery Voltage 90 80 8.192kHz, Iout = 2mA CLK pin C/4 pin Cx8 pin 70 fPUMP not present X X 0 32.768kHz low low 32.768kHz 32.768kHz, Iout = 10mA 262.14kHz, Iout = 40mA 60 50 3.0 3.3 3.6 3.9 4.2 Battery Voltage (V) 32.768kHz low high 262.14kHz 32.768kHz high low 8.192kHz Capacitor Selection 32.768kHz high high 262.14kHz In order to maintain the lowest output resistance, input ripple voltage and output ripple voltage, multi-layer ceramic capacitors with inherently low ESR are recommended. Refer to Table 2 for some suggested low ESR capacitors. Tables of output resistance and ripple voltages for a variety of input, output and pump capacitors are included here to use as a guide in capacitor selection. Measured conditions are with CLK = 32kHz, 5mA output load and all capacitors are 2.2uF except when stated otherwise. A DC power supply with added 0.25ohm output ESR was used to simulate a Lithium Ion Battery as shown in figure 5. Figure 4. Efficiency vs Battery Voltage Table 1. Control Line Logic for the Internal Charge Pump Oscillator Efficiency Power efficiency with the SP6680 charge pump regulator is improved over standard charge pumps doubler circuits by the inclusion of an 1.5X output mode, as described in the Theory of Operation section. The net result is an increase in efficiency at battery inputs greater than 3.7 to 3.8V where the SP6680 switches to the 1.5X mode. This is illustrated in figure 4 Efficiency vs Input Voltage. + Power Supply HP3631A 1000µF 0.25ohm 0.75” Leads - SP6680 EvBd 2.2µF Caps VIN (p-p) VOUT (p-p) Figure 5. Capacitor Selection Test Circuit Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 7 © Copyright 2004 Sipex Corporation MANUFACTURER / TELEPHONE # PART NUMBER CAPACITANCE / VOLTAGE MAX ESR @ 100kHz CAPACITOR SIZE / TYPE TDK / 847-803-6100 C2012X5R1A225K 2.2µF / 10V 0.030Ω 0805 / X5R TDK / 847-803-6100 C3216X5R1C475K 4.7µF / 10V 0.020Ω 1206 / X5R AVX / 843-448-9411 1206ZC225K 2.2µF / 10V 0.030Ω 1206 / X7R Taiyo Yuden / 847-925-0888 LMK212BJ225MG 2.2µF / 10V 0.030Ω 0805 / X5R Taiyo Yuden / 847-925-0888 LMK316BJ475ML 4.7µF / 10V 0.020Ω 1206 / X7R Figure 2. Suggested Low ESR Cermic Surface Mount Capacitors. Board Layout PC board layout is an important design consideration to mitigate switching current effects. High frequency operation makes PC layout important for minimizing ground bounc and noise. Components should be place as close to the IC as possible with connections made through short, low impedance traces. To maximize output ripple voltage, use a ground plane and solder the IC's GND pin directly to the ground plane. Output Resistance with Various Output and Pump Capacitors From Tables 3 & 4 it can be seen that increasing output capacitance alone reduces the output resistance more than increasing pump capacitance. This offers the advantage of increasing one capacitor versus two capacitors in the case for the pump capacitance. Table 3. Output Resistance vs Output Capacitance All Ceramic Capacitors ESR < 0.05ohm Cin, CF1, CF2 = 2.2uF, Vin = 3.85V, Iout = 5mA, CLK = 32kHz Cout (uF) SP6680 Rout (ohms) 0.47 57 1 28 2.2 18 4.7 13 10 11 22 10 Table 4. Output Resistance vs Pump Capacitance All Ceramic Capacitors ESR < 0.05ohm Cin, Cout = 2.2uF, Vin = 3.85V, Iout = 5mA, CLK = 32kHz CF1, CF2 (uF) SP6680 Rout (ohms) 0.47 39 1 24 2.2 18 4.7 15 10 14 22 13 Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 8 © Copyright 2004 Sipex Corporation Input Voltage Ripple with Various Input, Output and Pump Capacitors Looking at Tables 5, 6 & 7 it can be seen that increasing the value of the input capacitor (Table 5) reduces the input voltage ripple the most. Note that placement of this input bypass capacitor as close to the SP6680 input is recommended. Also note that Table 7 shows that increasing the pump capacitor beyond the values of the other capacitors (2.2uF) actually increases the input ripple voltage and is not recommended. Table 5. Input Voltage Ripple vs Input Capacitance All Ceramic Capacitors ESR < 0.05ohm Cout, CF1, CF2 = 2.2uF, Iout = 5mA, CLK = 32kHz Vin = 3.55V (In Regulation) Cin (uF) Vin Ripple mV (pp) 0.47 296 1 140 2.2 80 4.7 36 10 24 22 14 Vin = 3.85V (Not in Regulation) Vin Ripple mV (pp) 30 24 18 12 10 6 Table 6. Input Voltage Ripple vs Output Capacitance All Ceramic Capacitors ESR < 0.05ohm Cin, CF1, CF2 = 2.2uF, Iout = 5mA, CLK = 32kHz Vin = 3.55V (In Regulation) Vin = 3.85V (Not in Regulation) Cout (uF) Vin Ripple mV (pp) Vin Ripple mV (pp) 0.47 90 30 1 74 24 2.2 80 18 4.7 74 14 10 72 12 22 78 12 Table 7. Input Voltage Ripple vs Pump Capacitance All Ceramic Capacitors ESR < 0.05ohm Cin, Cout = 2.2uF, Iout = 5mA, CLK = 32kHz Vin = 3.55V (In Regulation) CF1, CF2 (uF) Vin Ripple mV (pp) 0.47 76 1 76 2.2 80 4.7 154 10 162 22 162 Date: 5/25/04 Vin = 3.85V (Not in Regulation) Vin Ripple mV (pp) 26 20 18 16 16 14 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 9 © Copyright 2004 Sipex Corporation Output Voltage Ripple with Various Input, Output and Pump Capacitors From Tables 8, 9 & 10 it appears that increasing pump capacitance will reduce output voltage ripple the most. But, as we saw previously in Table 7, input voltage ripple increases with increasing pump capacitance and it is not recommended to use pump capacitors greater than the other capacitor values. It is therefore recommended to use an output capacitor value equal to or slightly above the pump capacitor value. Note that for most designs the SP6680 output will be followed by a Low Dropout Regulator that will greatly reduce the output ripple. Table 8. Output Voltage Ripple vs Input Capacitance All Ceramic Capacitors ESR < 0.05ohm Cout, CF1, CF2 = 2.2uF, Iout = 5mA, CLK = 32kHz Vin = 3.55V (In Regulation) Vin = 3.85V (Not in Regulation) Cin (uF) Vout Ripple mV (pp) Vout Ripple mV (pp) 0.47 90 52 1 92 52 2.2 104 52 4.7 102 52 10 106 52 22 108 52 Table 9. Output Voltage Ripple vs Output Capacitance All Ceramic Capacitors ESR < 0.05ohm Cin, CF1, CF2 = 2.2uF, Iout = 5mA, CLK = 32kHz Vin = 3.55V (In Regulation) Vin = 3.85V (Not in Regulation) Cout (uF) Vout Ripple mV (pp) Vout Ripple mV (pp) 0.47 102 64 1 102 58 2.2 104 52 4.7 102 46 10 104 44 22 102 44 Table 10. Output Voltage Ripple vs Pump Capacitance All Ceramic Capacitors ESR < 0.05ohm Cin, Cout = 2.2uF, Iout = 5mA, CLK = 32kHz Vin = 3.55V (In Regulation) Vin = 3.85V (Not in Regulation) CF1, CF2 (uF) Vout Ripple mV (pp) Vout Ripple mV (pp) 0.47 365 200 1 172 108 2.2 108 52 4.7 90 24 10 76 14 22 40 8 Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 10 © Copyright 2004 Sipex Corporation PACKAGE: 10-PIN MSOP (ALL DIMENSIONS IN MILLIMETERS) D e1 Ø1 E/2 R1 R E1 E Gauge Plane L2 Seating Plane Ø1 Ø L L1 1 2 e Dimensions in (mm) 10-PIN MSOP JEDEC MO-187 (BA) Variation MIN TYP MAX A 0 A1 0 A2 0.75 b 0.17 0.27 c 0.08 0.23 D 1.1 0.015 0.85 0.95 b1 WITH PLATING 3.00 BSC. E 4.90 BSC. E1 3.00 BSC. e 0.50 BSC. e1 (b) c1 c 2.00 BSC. L 0.4 0.60 L1 0.95 L2 0.25 0.80 BASE METAL D 10 N R 0.07 R1 0.07 A2 Ø 0º 8º Ø1 0º 15º A b A1 1 Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 11 © Copyright 2004 Sipex Corporation ORDERING INFORMATION Part Number Temperature Range Package Type SP6680EU .............................................. -40˚C to +85˚C ........................................ 10-pin MSOP SP6680EU/TR ........................................ -40˚C to +85˚C ........................................ 10-pin MSOP Available in lead free packaging. To order add "-L" suffix to part number. Example: SP6680EU/TR = standard; SP6680EU-L/TR = lead free /TR = Tape and Reel Pack quantity is 2500 for MSOP. Corporation ANALOG EXCELLENCE Sipex Corporation Headquarters: 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600 Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others. Date: 5/25/04 SP6680 High Efficiency Buck/Boost Charge Pump Regulator 12 © Copyright 2004 Sipex Corporation