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_______________general description the max1044 and icl7660 are monolithic, cmos switched-capacitor voltage converters that invert, dou- ble, divide, or multiply a positive input voltage. they are pin compatible with the industry-standard icl7660 and ltc1044. operation is guaranteed from 1.5v to 10v with no external diode over the full temperature range. they deliver 10ma with a 0.5v output drop. the max1044 has a boost pin that raises the oscillator frequency above the audio band and reduces external capacitor size requirements. the max1044/icl7660 combine low quiescent current and high efficiency. oscillator control circuitry and four power mosfet switches are included on-chip. applications include generating a -5v supply from a +5v logic supply to power analog circuitry. for applica- tions requiring more power, the max660 delivers up to 100ma with a voltage drop of less than 0.65v. ________________________applications -5v supply from +5v logic supply personal communications equipment portable telephones op-amp power supplies eia/tia-232e and eia/tia-562 power supplies data-acquisition systems hand-held instruments panel meters ____________________________features ? miniature ?ax package ? 1.5v to 10.0v operating supply voltage range ? 98% typical power-conversion efficiency ? invert, double, divide, or multiply input voltages ? boost pin increases switching frequencies (max1044) ? no-load supply current: 200? max at 5v ? no external diode required for higher-voltage operation ______________ordering information ordering information continued at end of data sheet. * contact factory for dice specifications. max1044/icl7660 switched-capacitor voltage converters ________________________________________________________________ maxim integrated products 1 call toll free 1-800-998-8800 for free samples or literature. 19-4667; rev 1; 7/94 max1044 icl7660 4 3 2 1 cap- gnd cap+ (n.c.) boost 5 6 7 8 v out lv osc v+ top view ( ) are for icl7660 dip/so/?ax to-99 icl7660 n.c. cap+ gnd cap- v out lv osc v+ and case 1 2 3 4 5 6 7 8 _________________pin configurations negative voltage converter cap+ cap- v+ v out gnd input supply voltage negative output voltage max1044 icl7660 __________typical operating circuit dice* 8 so 8 plastic dip pin-package temp. range 0? to +70? 0? to +70? 0? to +70? max1044c/d max1044csa max1044 cpa part 8 plastic dip -40? to +85? max1044epa
max1044/icl7660 switched-capacitor voltage converters 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (circuit of figure 1, v+ = 5.0v, lv pin = 0v, boost pin = open, i load = 0ma, t a = t min to t max , unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note 1: the maxim icl7660 and max1044 can operate without an external output diode over the full temperature and voltage ranges. the maxim icl7660 can also be used with an external output diode in series with pin 5 (cathode at v out ) when replacing the intersil icl7660. tests are performed without diode in circuit. note 2: f osc is tested with c osc = 100pf to minimize the effects of test fixture capacitance loading. the 1pf frequency is correlat- ed to this 100pf test point, and is intended to simulate pin 7? capacitance when the device is plugged into a test socket with no external capacitor. for this test, the lv pin is connected to gnd for comparison to the original manufacturer? device, which automatically connects this pin to gnd for (v+ > 3v). supply voltage (v+ to gnd, or gnd to v out )....................10.5v input voltage on pins 1, 6, and 7 .........-0.3v v in (v+ + 0.3v) lv input current ..................................................................20? output short-circuit duration (v+ 5.5v)..................continuous continuous power dissipation (t a = +70?) plastic dip (derate 9.09mw/? above +70?) ............727mw so (derate 5.88mw/? above +70?) .........................471mw ?ax (derate 4.1mw/? above +70?) ......................330mw cerdip (derate 8.00mw/? above +70?) .................640mw to-99 (derate 6.67mw/? above +70?) ....................533mw operating temperature ranges max1044c_ _ /icl7660c_ _ ..............................0? to +70? max1044e_ _ /icl7660e_ _ ............................-40? to +85? max1044m_ _ /icl7660m_ _ ........................-55? to +125? storage temperature range ............................-65? to + 150? lead temperature (soldering, 10sec) .............................+300? khz t a = 0? to +70? t a = +25? t a = -55? to +125? v osc = 0v or v+, lv open r l = 5k , t a = +25?, f osc 5khz, lv open t a = -40? to +85? r l = 10k , lv open r l = 10k , lv to gnd f osc = 2.7khz (icl7660) , f osc = 1khz (max1044) , v+ = 2v, i l = 3ma, lv to gnd 30 200 r l = , pins 1 and 7 no connection, lv open ? 10 supply current 20 pin 1 = 0v pin 1 = v+ 3 oscillator sink or source current % 95 98 power efficiency c osc = 1pf, lv to gnd (note 2) 400 1 325 output resistance i l = 20ma, f osc = 5khz, lv open 200 t a = 0? to +70? t a = -40? to +85? 200 units max1044 min typ max parameter 325 t a = +25? 130 325 130 150 200 v 1.5 10 supply voltage range (note 1) 65 100 5 oscillator frequency 100 v+ = 2v v+ = 5v m 1.0 oscillator impedance 80 175 95 98 400 300 250 225 icl7660 min typ max 300 140 250 120 150 250 3.0 10.0 1.5 3.5 55 100 10 100 1.0 t a = -55? to +125? r l = , pins 1 and 7 = v+ = 3v t a = +25? t a = +25? t a = 0? to +70? t a = -40? to +85? t a = -55? to +125? v+ = 5v v+ = 2v r l = , t a = +25?, lv open 99.0 99.9 % 97.0 99.9 voltage conversion efficiency ? k conditions
80 90 100 30 10 1 efficiency vs. oscillator frequency 70 max1044-fig 7 oscillator frequency (hz) efficiency (%) 10 4 50 40 10 2 10 3 6x10 5 60 10 5 c1, c2 = 100? c1, c2 = 10? c1, c2 = 1? external hcmos oscillator 10,000 100,000 0.1 1 oscillator frequency vs. external capacitance 1000 max1044-fig 8 c osc (pf) oscillator frequency (hz) 1000 10 1 10 100 100,000 100 10,000 icl7660 and max1044 with boost = open max1044 with boost -v+ 100 1 oscillator frequency vs. supply voltage max1044-fig 9 supply voltage (v) oscillator frequency (hz) 4 10,000 1000 23 678910 100,000 5 from top to bottom at 5v max1044, boost = v+, lv = gnd max1044, boost = v+, lv = open icl7660, lv = gnd icl7660, lv = open max1044, boost = open, lv = gnd max1044, boost = open, lv = open 0 012345678910 output voltage and output ripple vs. load current -0.5 -2.0 max1044-fig 1 load current (ma) output voltage (v) output ripple (mvp-p) -1.5 -1.0 0 250 200 150 100 50 400 350 300 output voltage v+ = 2v lv = gnd output ripple a: max1044 with boost = v+ b: icl7660 c: max1044 with boost = open a b c 0 0 5 10 15 20 25 30 35 40 output voltage and output ripple vs. load current -0.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0 max1044-fig 2 load current (ma) output voltage (v) output ripple (mvp-p) -1.5 -1.0 0 720 640 560 480 400 320 240 160 80 800 output voltage output ripple v+ = 5v lv = open a a b c b c a: max1044 with boost = v+ b: icl7660 c: max1044 with boost = open 0 0 5 10 15 20 25 30 35 40 output voltage and output ripple vs. load current -1 -4 -5 -6 -7 -8 -9 -10 max1044-fig 3 load current (ma) output voltage (v) output ripple (mvp-p) -3 -2 0 700 630 560 490 420 350 280 210 140 70 v+ = 10v lv = open output ripple a b a: max1044 with boost = v+ b: icl7660 c: max1044 with boost = open c b c a output voltage 0 012345678910 efficiency and supply current vs. load current 10 40 50 60 70 80 90 100 max1044-fig 4 load current (ma) efficiency (%) supply current (ma) 30 20 0 7 8 9 10 6 5 4 3 2 1 supply current efficiency v+ = 2v lv = gnd 0 0 5 10 15 20 25 30 35 40 efficiency and supply current vs. load current 10 40 50 60 70 80 90 100 max1044-fig 5 load current (ma) efficiency (%) supply current (ma) 30 20 0 35 40 45 50 30 25 20 15 10 5 v+ = 5v lv = open efficiency a: max1044 with boost = v+ b: icl7660 c: max1044 with boost = open supply current b c a 0 0 5 10 15 20 25 30 35 40 efficiency and supply current vs. load current 10 40 50 60 70 80 90 100 max1044-fig 6 load current (ma) efficiency (%) supply current (ma) 30 20 0 35 40 45 50 30 25 20 15 10 5 v+ = 10v lv = open a: max1044 with boost = v+ b: icl7660 c: max1044 with boost = open supply current b, c efficiency a max1044/icl7660 switched-capacitor voltage converters _______________________________________________________________________________________ 3 __________________________________________typical operating characteristics (v+ = 5v; c bypass = 0.1?; c1 = c2 = 10?; lv = open; osc = open; t a = +25?; unless otherwise noted.)
0.1 1 2345678910 quiescent current vs. supply voltage max1044-fig 12 supply voltage (v) quiescent current (?) 10 1 100 1000 2000 a b d c a: max1044, boost = v+, lv = gnd b: max1044, boost = v+, lv = open c: icl7660 and max1044 with boost = open, lv = gnd; above 5v, max1044 only d: icl7660 and max1044 with boost = open, lv = open 0 10 1 10 2 10 3 10 4 10 5 output resistance vs. oscillator frequency max1044-fig 14 frequency (hz) resistance ( w ) 200 100 300 400 500 600 700 800 900 1000 c1, c2 = 100? c1, c2 = 1? c1, c2 = 10? external hcmos oscillator 0 -50 -25 0 25 50 75 100 125 quiescent current vs. temperature max1044-fig 13 temperature (?) quiescent current (?) 200 100 300 400 500 icl7660, max1044 with boost = open max1044 with boost = v+ 0 12345678910 output resistance vs. supply voltage max1044-fig 15 supply voltage (v) output resistance ( w ) 40 20 60 80 100 120 140 160 180 200 20 -60 -40 -20 0 20 40 60 80 100 120 140 output resistance vs. temperature max1044-fig 16 temperature (?) output resistance ( w ) 40 30 50 60 70 80 icl7660, max1044 with boost = open max1044 with boost = v+ max1044/icl7660 switched-capacitor voltage converters 4 _______________________________________________________________________________________ ____________________________typical operating characteristics (continued) (v+ = 5v; c bypass = 0.1?; c1 = c2 = 10?; lv = open; osc = open; t a = +25?; unless otherwise noted.) 0 -50 oscillator frequency vs. temperature max1044-fig 10 temperature (?) oscillator frequency (khz) 25 40 20 -25 0 75 100 125 60 80 100 50 a: max1044 with boost = v+ b: icl7600 c: max1044 with boost = open b a c 1 10 0 10 1 10 2 10 3 10 4 10 5 5x10 5 quiescent current vs. oscillator frequency max1044-fig 11 oscillator frequency (hz) quiescent current (?) 100 10 1000 10,000 using external hcmos oscillator using external capacitor
_______________detailed description the max1044/icl7660 are charge-pump voltage con- verters. they work by first accumulating charge in a bucket capacitor and then transfer it into a reservoir capacitor. the ideal voltage inverter circuit in figure 2 illustrates this operation. during the first half of each cycle, switches s1 & s3 close and switches s2 & s4 open, which connects the bucket capacitor c1 across v+ and charges c1. during the second half of each cycle, switches s2 & s4 close and switches s1 & s3 open, which connects the positive terminal of c1 to ground and shifts the nega- tive terminal to v out . this connects c1 in parallel with the reservoir capacitor c2. if the voltage across c2 is smaller than the voltage across c1, then charge flows from c1 to c2 until the voltages across them are equal. during successive cycles, c1 will continue pouring charge into c2 until the voltage across c2 reaches - (v+). in an actual voltage inverter, the output is less than - (v+) since the switches s1?4 have resistance and the load drains charge from c2. additional qualities of the max1044/icl7660 can be understood by using a switched-capacitor circuit model. switching the bucket capacitor, c1, between the input and output of the circuit synthesizes a resis- tance (figures 3a and 3b.) when the switch in figure 3a is in the left position, capacitor c1 charges to v+. when the switch moves to the right position, c1 is discharged to v out . the charge transferred per cycle is: ? q = c1(v+ - v out ). if the switch is cycled at frequency f, then the resulting max1044/icl7660 switched-capacitor voltage converters _______________________________________________________________________________________ 5 max1044 icl7660 boost cap+ gnd c bypass = 0.1? v+ r l cap- v+ osc c1 10 m f lv v out c2 10 m f c osc external oscillator v out _____________________________________________________________ pin description name function boost (max1044) frequency boost. connecting boost to v+ increases the oscillator frequency by a factor of six. when the oscillator is driven externally, boost has no effect and should be left open. pin 1 n.c. (icl7660) no connection 3 gnd ground. for most applications, the positive terminal of the reservoir capacitor is connected to this pin. 2 cap+ connection to positive terminal of charge-pump capacitor 6 lv low-voltage operation. connect to ground for supply voltages below 3.5v. icl7660: leave open for supply voltages above 5v. 5 v out negative voltage output. for most applications, the negative terminal of the reservoir capacitor is connected to this pin. 4 cap- connection to negative terminal of charge-pump capacitor 7 osc oscillator control input. connecting an external capacitor reduces the oscillator frequency. minimize stray capacitance at this pin. 8 v+ power-supply positive voltage input. (1.5v to 10v). v+ is also the substrate connection. figure 1. maxim max1044/icl7660 test circuit
max1044/icl7660 current is: i = f x ? q = f x c1(v+ - v out ). rewriting this equation in ohm? law form defines an equivalent resis- tance synthesized by the switched-capacitor circuit where: where f is one-half the oscillator frequency. this resis- tance is a major component of the output impedance of switched-capacitor circuits like the max1044/icl7660. as shown in figure 4, the max1044/icl7660 contain mosfet switches, the necessary transistor drive cir- cuitry, and a timing oscillator. ________________design information the max1044/icl7660 are designed to provide a simple, compact, low-cost solution where negative or doubled supply voltages are needed for a few low- power components. figure 5 shows the basic negative voltage converter circuit. for many applications, only two external capacitors are needed. the type of capacitor used is not critical. proper use of the low-voltage (lv) pin figure 4 shows an internal voltage regulator inside the max1044/icl7660. use the lv pin to bypass this regulator, in order to improve low-voltage performance i (v+ - v ) 1 / (f x c1) r 1 f x c1 out equiv = = and switched-capacitor voltage converters 6 _______________________________________________________________________________________ s1 v+ s2 s3 s4 c1 c2 v out = -(v+) figure 2. ideal voltage inverter v+ c1 f c2 r load v out figure 3a. switched capacitor model r equiv = r equiv v out r load 1 v+ f c1 c2 figure 3b. equivalent circuit 1m boost pin 1 osc pin 7 lv pin 6 gnd pin 3 cap- pin 4 s2 s1 s4 s3 cap+ pin 2 v+ pin 8 v out pin 5 ?2 q oscillator internal regulator q figure 4. max1044 and icl7660 functional diagram
and allow operation down to 1.5v. for low-voltage operation and compatibility with the industry-standard ltc1044 and icl7660, the lv pin should be connect- ed to ground for supply voltages below 3.5v and left open for supply voltages above 3.5v. the max1044? lv pin can be grounded for all operat- ing conditions. the advantage is improved low-voltage performance and increased oscillator frequency. the disadvantage is increased quiescent current and reduced efficiency at higher supply voltages. for maxim? icl7660, the lv pin must be left open for supply voltages above 5v. when operating at low supply voltages with lv open, connections to the lv, boost, and osc pins should be short or shielded to prevent emi from causing oscillator jitter. oscillator frequency considerations for normal operation, leave the boost and osc pins of the max1044/icl7660 open and use the nominal oscillator frequency. increasing the frequency reduces audio interference, output resistance, voltage ripple, and required capacitor sizes. decreasing frequency reduces quiescent current and improves efficiency. oscillator frequency specifications the max1044/icl7660 do not have a precise oscillator frequency. only minimum values of 1khz and 5khz for the max1044 and a typical value of 10khz for the icl7660 are specified. if a specific oscillator frequency is required, use an external oscillator to drive the osc pin. increasing oscillator frequency using the boost pin for the max1044, connecting the boost pin to the v+ pin raises the oscillator frequency by a factor of about 6. figure 6 shows this connection. higher frequency oper- ation lowers output impedance, reduces output ripple, allows the use of smaller capacitors, and shifts switch- ing noise out of the audio band. when the oscillator is driven externally, boost has no effect and should be left open. the boost pin should also be left open for normal operation. reducing the oscillator frequency using c osc an external capacitor can be connected to the osc pin to lower the oscillator frequency (figure 6). lower frequency operation improves efficiency at low load currents by reducing the ic? quiescent supply current. it also increases output ripple and output impedance. this can be offset by using larger values for c1 and c2. connections to the osc pin should be short to prevent stray capacitance from reducing the oscillator frequency. overdriving the osc pin with an external oscillator driving osc with an external oscillator is useful when the frequency must be synchronized, or when higher frequencies are required to reduce audio interference. the max1044/icl7660 can be driven up to 400khz. the pump and output ripple frequencies are one-half the external clock frequency. driving the max1044/icl7660 at a higher frequency increases the ripple frequency and allows the use of smaller capacitors. it also increases the quiescent current. the osc input threshold is v+ - 2.5v when v+ 3 5v, and is v+ / 2 for v+ < 5v. if the external clock does not swing all the way to v+, use a 10k pull-up resistor (figure 7). output voltage considerations the max1044/icl7660 output voltage is not regulated. the output voltages will vary under load according to the output resistance. the output resistance is primarily max1044/icl7660 switched-capacitor voltage converters _______________________________________________________________________________________ 7 max1044 icl7660 4 3 c1 10? *required for v+ < 3.5v v out = -(v+) c2 10? v+ 2 1 5 6 7 8 * c bypass figure 5. basic negative voltage converter max1044 4 3 10? c osc v out = -(v+) 10? v+ 2 1 5 6 7 8 connection from v+ to boost figure 6. negative voltage converter with c osc and boost
max1044/icl7660 a function of oscillator frequency and the capacitor value. oscillator frequency, in turn, is influenced by temperature and supply voltage. for example, with a 5v input voltage and 10? charge-pump capacitors, the output resistance is typically 50 . thus, the output voltage is about -5v under light loads, and decreases to about -4.5v with a 10ma load current. minor supply voltage variations that are inconsequential to digital circuits can affect some analog circuits. therefore, when using the max1044/icl7660 for powering sensitive analog circuits, the power-supply rejection ratio of those circuits must be considered. the output ripple and output drop increase under heavy loads. if necessary, the max1044/icl7660 out- put impedance can be reduced by paralleling devices, increasing the capacitance of c1 and c2, or connect- ing the max1044? boost pin to v+ to increase the oscillator frequency. inrush current and emi considerations during start-up, pump capacitors c1 and c2 must be charged. consequently, the max1044/icl7660 devel- op inrush currents during start-up. while operating, short bursts of current are drawn from the supply to c1, and then from c1 to c2 to replenish the charge drawn by the load during each charge-pump cycle. if the voltage converters are being powered by a high- impedance source, the supply voltage may drop too low during the current bursts for them to function prop- erly. furthermore, if the supply or ground impedance is too high, or if the traces between the converter ic and charge-pump capacitors are long or have large loops, switching noise and emi may be generated. to reduce these effects: 1) power the max1044/icl7600 from a low-impedance source. 2) add a power-supply bypass capacitor with low effective series resistance (esr) close to the ic between the v+ and ground pins. 3) shorten traces between the ic and the charge-pump capacitors. 4) arrange the components to keep the ground pins of the capacitors and the ic as close as possible. 5) leave extra copper on the board around the voltage converter as power and ground planes. this is easily done on a double-sided pc board. efficiency, output ripple, and output impedance the power efficiency of a switched-capacitor voltage converter is affected by the internal losses in the con- verter ic, resistive losses of the pump capacitors, and conversion losses during charge transfer between the capacitors. the total power loss is: the internal losses are associated with the ic? internal functions such as driving the switches, oscillator, etc. these losses are affected by operating conditions such as input voltage, temperature, frequency, and connec- tions to the lv, boost, and osc pins. the next two losses are associated with the output resistance of the voltage converter circuit. switch losses occur because of the on-resistances of the mosfet switches in the ic. charge-pump capacitor losses occur because of their esr. the relationship between these losses and the output resistance is as follows: where: and f osc is the oscillator frequency. r 1 (f / 2) x c1 4 2r esr esr out osc switches c1 c2 @+ + () + p p i x r out 2 out += ? p = p +p +p +p switched-capacitor voltage converters 8 _______________________________________________________________________________________ max1044 icl7660 4 3 10? v out = -(v+) 10? v+ v+ cmos or ttl gate 10k w required for ttl 2 1 5 6 7 8 figure 7. external clocking loss internal losses switch losses pump capacitor losses conversion losses pump capacitor losses switch losses
the first term is the effective resistance from the switched-capacitor circuit. conversion losses occur during the transfer of charge between capacitors c1 and c2 when there is a voltage difference between them. the power loss is: increasing efficiency efficiency can be improved by lowering output voltage ripple and output impedance. both output voltage rip- ple and output impedance can be reduced by using large capacitors with low esr. the output voltage ripple can be calculated by noting that the output current is supplied solely from capacitor c2 during one-half of the charge-pump cycle. slowing the oscillator frequency reduces quiescent cur- rent. the oscillator frequency can be reduced by con- necting a capacitor to the osc pin. reducing the oscillator frequency increases the ripple voltage in the max1044/icl7660. compensate by increasing the values of the bucket and reservoir capacitors. for example, in a negative voltage converter, the pump frequency is around 4khz or 5khz. with the recommended 10? bucket and reservoir capacitors, the circuit consumes about 70? of quiescent current while providing 20ma of output current. setting the oscillator to 400hz by connecting a 100pf capacitor to osc reduces the quiescent current to about 15?. maintaining 20ma output current capability requires increasing the bucket and reservoir capacitors to 100?. note that lower capacitor values can be used for lower output currents. for example, setting the oscillator to 40hz by connecting a 1000pf capacitor to osc pro- vides the highest efficiency possible. leaving the bucket and reservoir capacitors at 100? gives a maximum i out of 2ma, a no-load quiescent current of 10?, and a power conversion efficiency of 98%. general precautions 1) connecting any input terminal to voltages greater than v+ or less than ground may cause latchup. do not apply any input sources operating from external supplies before device power-up. 2) never exceed maximum supply voltage ratings. 3) do not connect c1 and c2 with the wrong polarity. 4) do not short v+ to ground for extended periods with supply voltages above 5.5v present on other pins. 5) ensure that v out (pin 5) does not go more positive than gnd (pin 3). adding a diode in parallel with c2, with the anode connected to v out and cathode to lv, will prevent this condition. ________________application circuits negative voltage converter figure 8 shows a negative voltage converter, the most popular application of the max1044/icl7660. only two external capacitors are needed. a third power-supply bypass capacitor is recommended (0.1? to 10?) v 1 2 x f x c2 2 x esr i ripple osc c2 out @+ ? ? ? ? p 1 2 c1 (v v 1 2 c2 v 2v v x f / 2 conv.loss out 2 ripple 2 out ripple osc ) =+- ? ? ? + ? - ? ? ? ? 2 max1044/icl7660 switched-capacitor voltage converters _______________________________________________________________________________________ 9 max1044 icl7660 4 3 c1 10? v out = -(v+) c bypass 0.1? 2 1 5 6 7 8 c2 10? v+ boost lv figure 8. negative voltage converter with boost and lv connections max1044 icl7660 4 3 v out = 2(v+) - 2v d 2 1 5 6 7 8 c1 c2 v+ figure 9. voltage doubler
max1044/icl7660 positive voltage doubler figure 9 illustrates the recommended voltage doubler circuit for the max1044/icl7660. to reduce the voltage drops contributed by the diodes (v d ), use schottky diodes. for true voltage doubling or higher output cur- rents, use the max660. voltage divider the voltage divider shown in figure 10 splits the power supply in half. a third capacitor can be added between v+ and v out . combined positive multiplication and negative voltage conversion figure 11 illustrates this dual-function circuit. capacitors c1 and c3 perform the bucket and reser- voir functions for generating the negative voltage. capacitors c2 and c4 are the bucket and reservoir capacitors for the doubled positive voltage. this circuit has higher output impedances resulting from the use of a common charge-pump driver. cascading devices larger negative multiples of the supply voltage can be obtained by cascading max1044/icl7660 devices (figure 12). the output voltage is nominally v out = -n(v+) where n is the number of devices cascaded. the out- put voltage is reduced slightly by the output resistance of the first device, multiplied by the quiescent current of the second, etc. three or more devices can be cascaded in this way, but output impedance rises dramatically. for example, the output resistance of two cascaded max1044s is approximately five times the output resis- tance of a single voltage converter. a better solution may be an inductive switching regulator, such as the max755, max759, max764, or max774. switched-capacitor voltage converters 10 ______________________________________________________________________________________ max1044 icl7660 4 3 2 1 5 6 7 8 c2 10? c1 10? v+ v out = v+ 1 2 lv figure 10. voltage divider max1044 icl7660 4 3 v out = 2(v+) - 2v d 2 1 5 6 7 8 c4 c1 c2 v+ v out = -(v+) c3 lv figure 11. combined positive and negative converter max1044 icl7660 4 3 2 1 5 6 7 8 max1044 icl7660 4 3 2 1 5 6 7 8 10? 10? v+ 10? 10? 10? v out = -n(v+) 10? max1044 icl7660 4 3 2 1 5 6 7 8 123 figure 12. cascading max1044/icl7660 for increased output voltage
paralleling devices paralleling multiple max1044/icl7660s reduces output resistance and increases current capability. as illus- trated in figure 13, each device requires its own pump capacitor c1, but the reservoir capacitor c2 serves all devices. the equation for calculating output resistance is: shutdown schemes figures 14a?4c illustrate three ways of adding shut- down capability to the max1044/icl7660. when using these circuits, be aware that the additional capacitive loading on the osc pin will reduce the oscillator fre- quency. the first circuit has the least loading on the osc pin and has the added advantage of controlling shutdown with a high or low logic level, depending on the orientation of the switching diode. r r (of max1044 or icl7660) n (number of devices) out out = max1044/icl7660 switched-capacitor voltage converters ______________________________________________________________________________________ 11 max1044 icl7660 4 3 v out = -(v+) 2 1 5 6 7 8 c2 c1 v+ max1044 icl7660 4 3 2 1 5 6 7 8 c1 1 n figure 13. paralleling max1044/icl7660 to reduce output resistance max1044 icl7660 4 3 10? v out = -(v+) 10? cmos or ttl gate 1n4148 v+ 2 1 5 6 7 8 v+ 10k w required for ttl figure 14a-14c. shutdown schemes for max1044/icl7660 output enable 74hc126 or 74ls126 tri-state buffer v+ 7 max1044 icl7660 74hc03 open-drain or 74ls03 open-collector nand gates v+ max1044 icl7660 7 a) b) c) 8 cerdip** 8 so pin-package temp. range -40? to +85? -55? to +125? max1044mja max1044esa part 8 plastic dip 0? to +70? icl7660 cpa 8 so 0? to +70? icl7660csa 8 ?ax 0? to +70? icl7660cua dice* 0? to +70? icl7660c/d 8 plastic dip -40? to +85? icl7660epa 8 so -40? to +85? icl7660esa 8 cerdip** -55? to +125? icl7660amja ? 8 to-99** -55? to +125? icl7660amtv ? _ordering information (continued) * contact factory for dice specifications. ** contact factory for availability. ? the maxim icl7660 meets or exceeds all ??and ?? specifications.
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 12 __________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 (408) 737-7600 1994 maxim integrated products printed usa is a registered trademark of maxim integrated products. max1044/icl7660 switched-capacitor voltage converters __________________________________________________________chip topographies gnd cap- lv v out transistor count: 71 substrate connected to v+ cap+ 0.084" (2.1mm) 0.060" (1.5mm) v+ osc icl7660 gnd cap+ boost 0.076" (1.930mm) 0.076" (1.930mm) cap- v out v+ osc lv transistor count: 72 substrate connected to v+ max1044 l a c a1 b dim a a1 b c d e e h l a min 0.036 0.004 0.010 0.005 0.116 0.116 0.188 0.016 0 max 0.044 0.008 0.014 0.007 0.120 0.120 0.198 0.026 6 min 0.91 0.10 0.25 0.13 2.95 2.95 4.78 0.41 0 max 1.11 0.20 0.36 0.18 3.05 3.05 5.03 0.66 6 inches millimeters 8-pin m max package 0.65 0.0256 21-0036 a e e h d 0.127mm 0.004 in ________________________________________________________package information
e nglish ? ???? ? ??? ? ??? what's ne w p roducts solutions de sign ap p note s sup p ort buy comp any me mbe rs m axim > p roduc ts > p ower and battery m anagement p rotec tion and i s olation icl7660, max1044 switched-c apacitor voltage c onverters 20ma charge pump with industry standard pinout quickview technical documents ordering info more information all ordering information notes: other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales . 1. didn't find what you need? ask our applications engineers. expert assistance in finding parts, usually within one business day. 2. part number suffixes: t or t&r = tape and reel; + = rohs/lead-free; # = rohs/lead-exempt. more: see full data sheet or part naming c onventions . 3. * some packages have variations, listed on the drawing. "pkgc ode/variation" tells which variation the product uses. 4. devices: 1-44 of 44 icl7660 fre e sam ple buy pack age : type pins footprint drawing code/var * te m p rohs/le ad-fre e ? m ate rials analys is ic l7660eja c eramic dip;8 pin;81 mm dwg: 21-0045a (pdf) use pkgcode/variation: j8-2 * -40c to +85c rohs/lead-free: no materials analysis ic l7660ija c eramic dip;8 pin;81 mm dwg: 21-0045a (pdf) use pkgcode/variation: j8-2 * -20c to +85c rohs/lead-free: no materials analysis ic l7660amja c eramic dip;8 pin;81 mm dwg: 21-0045a (pdf) use pkgcode/variation: j8-2 * -55c to +125c rohs/lead-free: no materials analysis ic l7660amja/883b c eramic dip;8 pin;81 mm dwg: 21-0045a (pdf) use pkgcode/variation: j8-2 * -55c to +125c rohs/lead-free: no materials analysis ic l7660c tv gold c an -to;8 pin;88 mm dwg: 21-0022a (pdf) use pkgcode/variation: g99-8 * 0c to +70c rohs/lead-free: no materials analysis ic l7660amtv gold c an -to;8 pin;88 mm dwg: 21-0022a (pdf) use pkgcode/variation: g99-8 * -55c to +125c rohs/lead-free: no materials analysis ic l7660amtv/883b gold c an -to;8 pin;88 mm dwg: 21-0022a (pdf) use pkgcode/variation: g99-8 * -55c to +125c rohs/lead-free: no materials analysis ic l7660amtv/hr metal c an-to;8 pin;88 mm dwg: 21-0022a (pdf) use pkgcode/variation: t99-8 * -55c to +125c rohs/lead-free: no materials analysis ic l7660epa+ pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8+1 * -40c to +85c rohs/lead-free: lead free materials analysis ic l7660ipa+ pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8+1 * -20c to +85c rohs/lead-free: see data sheet materials analysis ic l7660c pa+ pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8+1 * 0c to +70c rohs/lead-free: lead free materials analysis ic l7660c pa pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8-1 * 0c to +70c rohs/lead-free: no materials analysis
ic l7660epa pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8-1 * -40c to +85c rohs/lead-free: no materials analysis ic l7660ipa pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8-1 * -20c to +85c rohs/lead-free: no materials analysis ic l7660c sa soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-4 * 0c to +70c rohs/lead-free: no materials analysis ic l7660c sa+t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+4 * 0c to +70c rohs/lead-free: lead free materials analysis ic l7660c sa-t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-4 * 0c to +70c rohs/lead-free: no materials analysis ic l7660c sa+ soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+4 * 0c to +70c rohs/lead-free: lead free materials analysis ic l7660esa+t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+4 * -40c to +85c rohs/lead-free: lead free materials analysis ic l7660esa+ soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+4 * -40c to +85c rohs/lead-free: lead free materials analysis ic l7660esa-t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-4 * -40c to +85c rohs/lead-free: no materials analysis ic l7660esa soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-4 * -40c to +85c rohs/lead-free: no materials analysis ic l7660isa-t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-4 * -20c to +85c rohs/lead-free: no materials analysis ic l7660isa+t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+4 * -20c to +85c rohs/lead-free: lead free materials analysis ic l7660isa+ soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+4 * -20c to +85c rohs/lead-free: lead free materials analysis ic l7660isa soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-4 * -20c to +85c rohs/lead-free: no materials analysis ic l7660c ua+t umax;8 pin;16 mm dwg: 21-0036j (pdf) use pkgcode/variation: u8+1 * 0c to +70c rohs/lead-free: lead free materials analysis ic l7660c ua+ umax;8 pin;16 mm dwg: 21-0036j (pdf) use pkgcode/variation: u8+1 * 0c to +70c rohs/lead-free: lead free materials analysis ic l7660c ua umax;8 pin;16 mm dwg: 21-0036j (pdf) use pkgcode/variation: u8-1 * 0c to +70c rohs/lead-free: no materials analysis ic l7660c ua-t umax;8 pin;16 mm dwg: 21-0036j (pdf) use pkgcode/variation: u8-1 * 0c to +70c rohs/lead-free: no materials analysis m ax1044 fre e sam ple buy pack age : type pins footprint drawing code/var * te m p rohs/le ad-fre e ? m ate rials analys is max1044mja c eramic dip;8 pin;81 mm dwg: 21-0045a (pdf) use pkgcode/variation: j8-2 * -55c to +125c rohs/lead-free: no materials analysis max1044mja/883b c eramic dip;8 pin;81 mm dwg: 21-0045a (pdf) use pkgcode/variation: j8-2 * -55c to +125c rohs/lead-free: no materials analysis max1044epa+ pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8+1 * -40c to +85c rohs/lead-free: lead free materials analysis max1044c pa+ pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8+1 * 0c to +70c rohs/lead-free: lead free materials analysis
max1044c pa pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8-1 * 0c to +70c rohs/lead-free: no materials analysis max1044epa pdip;8 pin;82 mm dwg: 21-0043d (pdf) use pkgcode/variation: p8-1 * -40c to +85c rohs/lead-free: no materials analysis max1044c sa soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-2 * 0c to +70c rohs/lead-free: no materials analysis max1044c sa-t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-2 * 0c to +70c rohs/lead-free: no materials analysis max1044c sa+t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+2 * 0c to +70c rohs/lead-free: lead free materials analysis max1044c sa+ soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+2 * 0c to +70c rohs/lead-free: lead free materials analysis max1044esa+t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+2 * -40c to +85c rohs/lead-free: lead free materials analysis max1044esa soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-2 * -40c to +85c rohs/lead-free: no materials analysis max1044esa-t soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8-2 * -40c to +85c rohs/lead-free: no materials analysis max1044esa+ soic ;8 pin;31 mm dwg: 21-0041b (pdf) use pkgcode/variation: s8+2 * -40c to +85c rohs/lead-free: lead free materials analysis didn't find what you need? next day product selection assistance from applications engineers parametric search applications help quickview technical documents ordering info more information des c ription key features a pplic ations /u s es key spec ific ations diagram data sheet a pplic ation n otes des ign guides e ngineering journals reliability reports software/m odels e valuation kits p ric e and a vailability samples buy o nline p ac kage i nformation lead-free i nformation related p roduc ts n otes and c omments e valuation kits doc ument ref.: 1 9 -4 6 6 7 ; rev 1 ; 1 9 9 4 -0 7 -2 8 t his page las t modified: 2 0 0 7 -0 5 -2 9 c ontac t us: send us an email c opyright 2 0 0 7 by m axim i ntegrated p roduc ts , dallas semic onduc tor ? legal n otic es ? p rivac y p olic y

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