SP6644 EXAR | Alldatasheet
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Technical content
Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation SP6644/6645 Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator ■ 90mA Output Current at 1.3V Input ■ 190mA Output Current at 2.6V Input ■ +2V to +5.5V Output Range ■ 0.88V Guaranteed Start-Up ■ 92% High Efficiency ■ 1.6µA Quiescent Supply Current at VBATT ■ Reverse Battery Protection ■ Internal Synchronous Rectifier ■ 5nA Logic Controlled Shutdown Current From VBATT ■ Low-Battery Detection Active LOW Output GND FB LXVBATT 47µF 47µF R LIM +3.3VOUT SHDN 22µH 0.7A 0.88V to 3.3V Input SP6644 SP6645 BATTLO VOUT
DESCRIPTION
The SP6644/6645 devices are high-efficiency, low-power step-up DC-DC converters ideal for single or dual alkaline cell applications such as pagers, remote controls, pointing devices, medical monitors, and other low-power portable end products. Designers can control the SP6644 device with an active LOW shutdown input. The SP6644 device features an active low output for batteries below +1.0V. The SP6645 device features an active low output for batteries below +2.0V. Both devices contain a 0.8Ω synchronous rectifier, a 0.5Ω N-channel MOSFET power switch, an internal voltage reference, circuitry for pulse- frequency-modulation, and an under voltage comparator. The output voltage for the SP6644/6645 devices is preset to +3.3V + 4% or can be adjusted from +2V to +5.5V by manipulating two external resistors TYPICAL APPLICATION CIRCUIT SP6644 SP6645
8 Pin MSOP
Now Available in Lead Free Packaging ■ Small 8 Pin MSOP Package ■ No External FETs ■ Flexibility to Optimize Inductor Type with Programmable Peak Current Control
Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation 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. V Reverse battery Current, T (NOTE 1) V Power Dissipation Per Package 8-pin µSOIC VBATT = VSHDN = 1.3V, ILOAD = 0mA, FB = GND, TAMB = -40oC to +85oC, and typical values are at TAMB = +25oC unless otherwise noted.
ELECTRICAL CHARACTERISTICS
RETEMARAP. NIM. PYT. XAMS TINU ♦♦♦♦♦ SNOITIDNOC ,egatloVtupnIgnitarepOmumixaM V )XAM(TTAB V,egatloVtupnIpU-tratS TTAB 28.01 .1V ♦♦♦♦♦ R L k3= Ω , V,egatloVtupnIpU-tratS TTAB tneiciffeoCerutarepmeT 1- CºVm egatloVtupnINDHS V LI V HI 08 51% V fo% TTAB Vfo% TTAB tnerruCtupnINDHS1 0 01A n ♦♦♦♦♦ tnerruCtupnIBF1 0 01A n ♦♦♦♦♦ V BF ,V3.1= V,egatloVteSBF BF 512.12 62.19 03.1V ♦♦♦♦♦ kcabdeeflanretxe egatloVpirTgnillaFOLTTAB4 9.0 88.1 00.1 00.2 60.1 21.2 V ♦♦♦♦♦ V,4466PS TUO V3.3= V,5466PS TUO V3.3= V,egatloVtuptuO TUO 61.30 3.34 4.3V ♦♦♦♦♦ V BF V1.0< egnaRegatloVtuptuO0 .25 .5V ♦♦♦♦♦ kcabdeeflanretxe ecnatsiseR-nOlennahC-N5 .00 .1 Ω V TUO V3.3= ecnatsiseR-nOlennahC-P8 .06 .1 Ω V TUO V3.3= ABSOLUTE MAXIMUM RATINGS
Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation VBATT = VSHDN = 1.3V, ILOAD = 0mA, FB = GND, TAMB = -40oC to +85oC, and typical values are at TAMB = +25oC unless otherwise noted. NOTE 1: The reverse battery current is measured from the Typical Operating Circuit's input terminal to GND when the battery is connected backward. A reverse current of 220mA will not exceed package dissipation limits but, if left for an extended time (more than 10 minutes), may degrade performance. NOTE 2: Specifications to -40 oC are guaranteed by design, not production tested. NOTE 3: Inductor Peak Current where .IPEAK = 1400 R LIM RETEMARAP. NIM. PYT. XAMS TINUS NOITIDNOC VotnitnerruCtnecseiuQ TUO I, TUOQ 050 8 µA ♦♦♦♦♦ V TUO V5.3= VotnitnerruCtnecseiuQ TTAB I, TTABQ 6.10 .3 µA ♦♦♦♦♦ V TTAB V0.1= VotnitnerruCnwodtuhS TUO I, TUONDHS 100.05 .0 µA ♦♦♦♦♦ V TUO V,V5.3= NDHS V0- VotnitnerruCnwodtuhS TTAB I, TTABNDHS 500.01 .0 µA ♦♦♦♦♦ V TTAB V,V0.1= NDHS V0- V,OLTTABrofegatloVtuptuOwoL LO 4.0V ♦♦♦♦♦ V TTAB V,V9.0= TUO I,V3.3+= KNIS Am1= OLTTABroftnerruCegakaeL1 µA ♦♦♦♦♦ V TTAB V,V6.2= OLTTAB V5.3= ycneiciffE9 8% ♦♦♦♦♦ I DAOL V,Am051= TTAB V6.2= I,tnerruCkaeProtcudnI KAEP 5720 530 04A m ♦♦♦♦♦ R MIL k5= Ω 3ETON, )OLVU(tuo-kcoLegatloVrednU0 05.00 27.0V ♦♦♦♦♦
Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation The SP6644/6645 devices are high-efficiency, low-power step-up DC-DC converters ideal for single or dual alkaline cell applications such as pagers, remote controls, and other low-power portable end products. The SP6644/6645 devices feature a 5nA logic- controlled shutdown mode and a dedicated low-battery detector circuitry. Both devices contain a 0.8Ω synchronous rectifier, a 0.5Ω N-channel MOSFET power switch, an internal voltage reference, circuitry for pulse-frequency- modulation, and an under voltage comparator. The output voltage for the SP6644/6645 devices can be adjusted from +2V to +5.5V by manipulating two external resistors. The output voltage is preset to +3.3V. THEORY OF OPERATION The SP6644/6645 devices are ideal for end products that function with a single or dual alkaline cell, such as remote controls, pagers, and other portable consumer products. Designers can implement the SP6644/6645 devices into applications with the following power management operating states: 1. where the primary battery is good and the load is active, and 2. where the primary battery is good and the load is sleeping. In the first operating state where the primary supply is good and the load is active, the SP6644/6645 devices typically offer 88% efficiency, drawing tens of milliamps. Applications will predominantly operate in the second state where the primary supply is good and the load is sleeping. The SP6644/6645 devices draw a very low quiescent current while the load in its disabled state will draw typically hundreds of microamps. The pulse-frequency-modulation (PFM) circuitry provides higher efficiencies at low to moderate output loads than traditional PWM converters are capable of delivering. In a state where the error comparator detects that the output voltage at V OUT is too low, the internal N-channel MOSFET switch is turned on until the peak inductor current is satisfied. This is indicated by the falling edge of the I-Charge comparator output. The approximate inductor charging time is defined by: t CHARGE ≅≅≅≅≅ L x IPEAK / VBATT where tCHARGE [s] is the approximate inductor charging time, L [H] is the inductance, IPEAK [A] is the peak inductor current, and VBATT [V] is the input voltage to the device. The peak inductor current, IPEAK , is programmed externally by putting a resistor between the RLIM pin and ground. This is defined by: IPEAK = 1400 R LIM where IPEAK [A] is the peak inductor current and R LIM [Ω] is the value of the resistor connected from pin RLIM to ground. When the charging N MOSFET turns off, the discharging P MOSFET turns on and the inductor current flows into the output capacitor and the load recharging the output. When the current through the discharging P MOSFET approaches zero, the I-Discharge comparator indicates to the logic to turn off the P MOSFET. The approximate time for discharging the inductor current can be determined by: t VOUT - VBATT where tDCHG [s] is the time to discharge the inductor, L [H] is the inductance, IPEAK [A] is the peak inductor current, VOUT [V] is the output voltage, and VBATT [V] is the input voltage to the device. The output filter capacitor stores charge while current from the inductor is high and holds the output voltage high until the discharge phase of the next switching cycle, smoothing power flow to the load. Between switching cycles, the inductor damping switch is closed suppressing the ringing caused by the inductor and the parasitic capacitance on the LX node.
Figure 27. Internal Block Diagram of the SP6644/6645
- Once started, the output voltage can maintain
same manner with a threshold voltage of 2V. body diode from the input to the output. Figure 28. FB regulates to +1.25V. voltage, and VREF [V] is 1.25V. current can degrade performance of the devices. reliability problems with the application circuit.
the device, and VOUT [V] is the output voltage. reduce possible EMI and output ripple voltage. Figure 28. Adjustable Output Voltage Circuitry internal ground plane using vias.
60%. Low ESR capacitors are recommended. Ceramic capacitors have the lowest ESR. stepping up from 1.3V to 3.3V at 20mA. frequency for the specified load and input voltage. tion can be seen in figures 17 to 20. Table 1. Surface-Mount Inductor Information
Figure 29. Schematic SP6644/6201 DC/DC LDO Combination
Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation PACKAGE: 8 PIN MSOP L ØØ1 R Seating Plane E/2 E D Gauge PlaneL2 Pin #1 indentifier must be indicated within this shaded area (D/2 * E1/2) e A2 A b B B SYMBOL MIN NOM MAX A- - 1.1 A1 0 - 0.15 A2 0.75 0.85 0.95 b 0.22 - 0.38 c 0.08 - 0.23 D E e L 0.4 0.6 0.8 N- 8 - R 0.07 - - R1 0.07 - - ø0 º - 8 º ø1 0º - 15º Note: Dimensions in (mm)
0.65 BSC
1.95 BSC
0.95 REF
0.25 BSC
8 Pin MSOP JEDEC MO-187 (AA) Variation
3.00 BSC
4.90 BSC
c WITH PLATING BASE METAL b Section B-B
Date: 11/30/04 SP6644/6645 High Efficiency Boost Regulator © Copyright 2004 Sipex Corporation Part Number Temperature Range Package Type Corporation ANALOG EXCELLENCE 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 herein; neither does it convey any license under its patent rights nor the rights of others. Sipex Corporation Headquarters and Sales Office
22 Linnell Circle
Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: sales@sipex.com
ORDERING INFORMATION
/TR = Tape and Reel Pack quantity is 2500 for MSOP. Available in lead free packaging. To order add "-L" suffix to part number. Example: SP6644EU/TR = standard; SP6644EU-L/TR = lead free