rev 1.6 6/22/04 1 of 9 www.xicor.com dual digitally controlled potentiometers (xdcps ? ) X93256 features dual solid-state potentiometers individual up/down interfaces 32 wiper tap points per potentiometer ?wiper position stored in nonvolatile memory and recalled on power-up 31 resistive elements per potentiometer ?temperature compensated ?maximum resistance tolerance of 25% ?terminal voltage, 0 to v cc low power cmos ?v cc = 2.7 v - 5.5 v. ?active current, 200a typical per potentio- meter ?standby current, 4a max per potentiometer high reliability ?endurance 200,000 data changes per bit ?register data retention, 100 years r total value = 12.5k ? , 50k ? packages ?14-lead tssop description the xicor X93256 is a dual digitally controlled potentiometer (xdcp). the device consists of two resistor arrays, wiper switches, a control section, and nonvolatile memory. the wiper positions are controlled by individual up/down interfaces. a potentiometer is implemented by a resistor array composed of 31 resistive elements and a wiper switching network. the position of each wiper element is controlled by a set of independent cs , u/d , and inc inputs. the position of the wiper can be stored in nonvolatile memory and then be recalled upon a subsequent power-up operation. each potentiometer is connected as a three-terminal variable resistor and can be used in a wide variety of applications including: ? bias and gain control ? lcd contrast adjustment a pplication n ote a v a i l a b l e an20 ? an42?53 an71 an73 an88 an91?92 an99 an115 an120 an124 an133 an134 an135 xdcp ? is a trademark of xicor, inc. block diagram 5-bit up/down counter 5-bit nonvolatile memory store and recall control circuitry one of decoder resistor array r h1 u/d 1 inc 1 cs 1 transfer gates thirty v cc v ss r l1 general description detailed single potentiometer description 0 1 2 28 29 30 31 two control and memory up/down (u/d 1 & u/d 2 ) increment (inc 1 & inc 2 ) device select (cs 1 & cs 2 ) v cc (supply voltage) v ss (ground) r h1 r l1 30k r h2 r l2 r w r w1 r w2
2 of 9 rev 1.6 6/22/04 www.xicor.com X93256 pin configuration X93256 ordering codes pin descriptions ordering number rtotal package temperature range X93256wv14i-2.7 12.5 k ? 14-lead tssop package -40c to +85c X93256uv14i-2.7 50 k ? 14-lead tssop package -40c to +85c tssop symbol brief description 1r w1 r w1 . the r w1 pin of the X93256 is the wiper terminal of the first potentiometer which is equivalent to the movable terminal of a mechanical potentiometer. 2r l1 r l1 . the r h1 and r l1 pins of the X93256 are equivalent to the fixed terminals of a mechanical potentiometer. the minimum voltage is v ss and the maximum is v cc . the terminol- ogy of r h1 and r l1 references the relative position of the terminal in relation to wiper movement direction selected by the u/d input. 3cs 1 chip select 1 (cs 1 ) . the first potentiometer is selected when the cs 1 input is low. the current counter value is stored in nonvolatile memory when cs 1 is returned high while the inc 1 input is also high. after the store operation is complete, the first potentiometer of the X93256 will be placed in the low power standby mode until the first potentiometer is selected once again. 4inc 2 increment 2 (inc 2 ) . the inc 2 input is negative-edge triggered. toggling inc 2 will move the wiper of the second potentiometer and either increment or decrement the counter in the direction indi- cated by the logic level on the u/d 2 input. 5u/d 2 up/down 2 (u/d 2 ) . the u/d 2 input controls the direction of the second potentiometer wiper movement and whether the counter for the second potentiometer is incremented or decremented. 6r h2 r h2 . the r h 2 and r l2 pins of the X93256 are equivalent to the fixed terminals of a mechanical potentiometer. the minimum voltage is v ss and the maximum is v cc . the terminol- ogy of r h2 and r l2 references the relative position of the wiper terminal for the second potenti- ometer in relation to the wiper movement direction selected by the u/d 2 input. 7v ss ground . 8r w2 r w2 . the r w2 pin of the X93256 is the wiper terminal of the second potentiometer which is equiv- alent to the movable terminal of a mechanical potentiometer. v cc cs 1 inc 2 u/d 2 r h2 v ss 1 2 3 4 8 7 6 5 X93256 tssop r l1 * nc can be left unconnected, or connected to any voltage between v ss and v cc . cs 2 inc 1 u/d 1 r h1 r l2 14 13 12 11 9 10 rw1 rw2
3 of 9 rev 1.6 6/22/04 www.xicor.com X93256 9r l2 r l2 . the r h2 and r l2 pins of the X93256 are equivalent to the fixed terminals of a mechanical potentiometer. the minimum voltage is v ss and the maximum is v cc . the terminol- ogy of r h2 and r l2 references the relative position of the wiper terminal for the second potenti- ometer in relation to the wiper movement direction selected by the u/d 2 input. 10 cs 2 chip select 2 (cs 2 ) . the second potentiometer is selected when the cs 2 input is low. the cur- rent counter value is stored in nonvolatile memory when cs 2 is returned high while the inc 2 in- put is also high. after the store operation is complete, the second potentiometer of the X93256 will be placed in the low power standby mode until the second potentiometer is selected once again. 11 v cc supply voltage . 12 inc 1 increment 1(inc 1 ) . the inc 1 input is negative-edge triggered. toggling inc 1 will move the wiper of the first potentiometer and either increment or decrement the counter in the direction indicated by the logic level on the u/d 1 input. 13 u/d 1 up/down 1 (u/d 1 ) . the u/d 1 input controls the direction of the first potentiometer wiper move- ment and whether the counter for the first potentiometer is incremented or decremented. 14 r h1 r h1 . the r h 1 and r l1 pins of the X93256 are equivalent to the fixed terminals of a mechanical potentiometer. the minimum voltage is v ss and the maximum is v cc . the terminol- ogy of r h1 and r l1 references the relative position of the wiper terminal for the first potentiometer in relation to the wiper movement direction selected by the u/d 1 input. tssop symbol brief description
X93256 4 of 9 rev 1.6 6/22/04 www.xicor.com absolute maximum ratings temperature under bias ....................?65 c to +135 c storage temperature .........................?65c to +150c voltage on cs , inc , u/d , r h , r l and v cc with respect to v ss ..............................?1v to +6.5v lead temperature (soldering 10 seconds)......... 300c maximum reflow temperature (40 seconds) ...... 240c maximum resistor current..................................... 2ma comment stresses above those listed under ?absolute maximum ratings? may cause permanent damage to the device. this is a stress rating only; the functional operation of the device (at these or any other conditions above those listed in the operational sections of this specification) is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. recommended operating conditions potentiometer characteristics (over recommended operating conditions unless otherwise stated.) notes: (1) absolute linearity is utilized to determine actual wiper voltage versus expected voltage = (v h(n) (actual)?v h(n) (expected)) = 1 ml maximum. n = 1 .. 29 only. (2) relative linearity is a measure of t he error in step size between taps = v h(n+1) ?[v h(n) + ml] = 0.5 ml, n = 1 .. 29 only. (3) 1 ml = minimum increment = r tot /31. (4) typical values are for t a = 25c and nominal supply voltage. (5) this parameter only applies to a single potentiometer. (6) typical parameter is guaranteed by characterization. (7) when performing multiple write operations, v cc must not decrease by more than 150mv from it?s initial value. temperature min. max. industrial ?40c +85c supply voltage (v cc )limits X93256 2.7v to 5.5v (7) symbol parameter limits test conditions/notes min. typ. max. unit r tot end to end resistance 9.375 12.5 15.625 k ? w option (5) 37.5 50 62.5 k ? u option (5) v r r h , r l terminal voltages 0 v cc v (5) power rating 1 mw (7) r total = 50 k ? (5) (6) noise -120 dbv (7) ref: 1khz (5) (6) r w wiper resistance 1100 ? (5) (6) i w wiper current 0.6 ma (5) (6) resolution 3 % (5) absolute linearity (1) 1 mi (3) v h(n)(actual) ?v h(n)(expected) (5) relative linearity (2) 0.5 mi (3) v h(n+1) ?[v h(n)+mi ] (5) r total temperature coefficient 35 ppm/c (5) (6) c h /c l /c w potentiometer capacitances 10/10/25 pf (6) see circuit #2 (5)
5 of 9 rev 1.6 6/22/04 www.xicor.com X93256 d.c. operating characteristics (over recommended operating conditions unless otherwise specified.) endurance and data retention test circuit #1 circuit #2 spice macro model a.c. conditions of test symbol parameter limits unit test conditions min. typ. (4) max. i cc1 v cc active current (increment) 50 250 a cs = v il , u/d = v il or v ih and inc = 0.4v @ max. t cyc v cc =3v 200 300 cs = v il , u/d = v il or v ih and inc = 0.4v @ max. t cyc v cc =5v i cc2 v cc active current (store) (eeprom store) 600 a cs = v ih , u/d = v il or v ih and inc = v ih @ max. t wr v cc =3v 1400 a cs = v ih , u/d = v il or v ih and inc = v ih @ max. t wr v cc =5v i sb standby supply current 1 a cs = v cc ? 0.3v, u/d and inc = v ss or v cc ? 0.3v v cc =3v 4a cs = v cc ? 0.3v, u/d and inc = v ss or v cc ? 0.3v v cc =5v i li cs input leakage current 1 a v in = v cc (5) i li cs input leakage current 60 100 150 a v cc = 3v, cs = 0 (5) i li cs input leakage current 120 200 250 a v cc = 5v, cs = 0 (5) i li inc , u/d input leakage current 1 a v in = v ss to v cc (5) v ih cs , inc , u/d input high voltage v cc x 0.7 v cc + 0.5 v (5) v il cs , inc , u/d input low voltage ?0.5 v cc x 0.1 v (5) c in (5)(7) cs , inc , u/d input capacitance 10 pf v cc = 3v, v in = v ss , t a = 25c, f = 1mhz (6) parameter min. unit minimum endurance 200,000 data changes per bit data retention 100 years test point v h /r h c h c l 10pf 10pf r h r total c w 25pf r l input pulse levels 0v to 3v input rise and fall times 10ns input reference levels 1.5v
X93256 6 of 9 rev 1.6 6/22/04 www.xicor.com a.c. operating characteristics (over recommended operating conditions unless otherwise specified) power up and down requirements there are no restrictions on the power-up or power-down conditions of v cc and the voltages applied to the potentiometer pins provided that v cc is always more positive than or equal to v h and v l , i.e., v cc v h, v l . the v cc ramp rate spec is always in effect. a.c. timing symbol parameter limits unit min. typ. (6) max. t cl cs to inc setup 100 ns t ld inc high to u/d change 100 ns t di u/d to inc setup 100 ns t ll inc low period 1 s t lh inc high period 1 s t lc inc inactive to cs inactive 1 s t cph cs deselect time (no store) 250 ns t cph cs deselect time (store) 10 ms t cyc inc cycle time 2 s t r , t f (6) inc input rise and fall time 500 s t r v cc (6) v cc power-up rate 0.2 10,000 v/ms t wr store cycle 5 10 ms cs inc u/d t ci t il t ih t cyc t id t di t ic t cph t f t r 10% 90% 90% (store)
7 of 9 rev 1.6 6/22/04 www.xicor.com X93256 pin descriptions (in the text, cs , inc , u/d , r h , r w , and r l are used to refer to either cs 1 or cs 2 , etc. note: these signals can be applied independently or at the same time.) r h and r l the r h and r l pins of the X93256 are equivalent to the fixed terminals of a mechanical potentiometer. the minimum voltage is v ss and the maximum is v cc . the terminology of r h and r l references the relative position of the terminal in relation to wiper movement direction selected by the u/d input per potentiometer. r w the r w pin of the X93256 is the wiper terminal of the potentiometer which is equivalent to the movable terminal of a mechanical potentiometer up/down (u/d ) the u/d input controls the direction of a single potentiometer?s wiper movement and whether the counter is incremented or decremented. increment (inc ) the inc input is negative-edge triggered. toggling inc will move the wiper and either increment or decrement the pertatining potentiometer?s counter in the direction indicated by the logic level on the pertaining potentiometer?s u/d input. chip select (cs ) a potentiometer is selected when the pertaining cs input is low. its current counter value is stored in nonvolatile memory when the pertaining cs is returned high while the pertaining inc input is also high. after the store operation is complete the affected potentiometer will be placed in the low power standby mode until the potentiometer is selected once again. principles of operation there are multiple sections for each potentiometer in the X93256: an input control, a counter and decode section; the nonvolatile memory; and a resistor array. each input control section operates just like an up/down counter. the output of this counter is decoded to turn on a single electronic switch connecting a point on the resistor array to the wiper output. under the proper conditions the contents of the counter can be stored in nonvolatile memory and retained for future use. each resistor array is comprised of 31 individual resistors connected in series. at either end of the array and between each resistor is an electronic switch that transfers the connection at that point to the wiper. each wiper, when at either fixed terminal, acts like its mechanical equivalent and does not move beyond the last position. that is, the counter does not wrap around when clocked to either extreme. if the wiper is moved several positions, multiple taps are connected to the wiper for t iw (inc to v w change). the 2- terminal resistance value for the device can temporarily change by a significant amount if the wiper is moved several positions. when the device is powered-down, the last wiper position stored will be maintained in the nonvolatile memory for each potentiometer. when power is restored, the contents of the memory are recalled and each wiper is set to the value last stored.
X93256 8 of 9 rev 1.6 6/22/04 www.xicor.com instructions and programming the inc , u/d and cs inputs control the movement of the pertaining wiper along the resistor array. with cs set low the pertaining potentiometer is selected and enabled to respond to the u/d and inc inputs. high to low transitions on inc will increment or decrement (depending on the state of the u/d input) a five bit counter. the output of this counter is decoded to select one of thirty two wiper positions along the resistive array. the value of the counter is stored in nonvolatile memory whenever each cs transitions high while the pertaining inc input is also high. in order to avoid an accidental store during power-up, each cs must go high with v cc during initial power-up. when left open, each cs pin is internally pulled up to v cc by an internal 30k resistor. the system may select the X93256, move any wiper and deselect the device without having to store the latest wiper position in nonvolatile memory. after the wiper movement is performed as described above and once the new position is reached, the system must keep inc low while taking cs high. the new wiper position will be maintained until changed by the system or until a power- up/down cycle recalled the previously stored data. in order to recall the stored position of the wiper on power- up, the cs pin must be held high. this procedure allows the system to always power-up to a preset value stored in nonvolatile memory; then during system operation minor adju stments could be made. the adjustments might be based on user preference, system parameter changes due to temperature drift, or other system trim requirements. the state of u/d may be changed while cs remains low. this allows the host system to enable the device and then move each wiper up and down until the proper trim is attained. mode selection symbol table cs inc u/d mode l h wiper up l l wiper down h x store wiper position h x x standby current l x no store, return to standby l h wiper up (not recommended) l l wiper down (not recommended) waveform inputs outputs must be steady will be steady may change from low to high will change from low to high may change from high to low will change from high to low don?t care: changes allowed changing: state not known n/a center line is high impedance
characteristics subject to change without notice. 9 of 9 limited warranty devices sold by xicor, inc. are covered by the warranty and patent indemnification provisions appearing in its terms of sale on ly. xicor, inc. makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the descr ibed devices from patent infringement. xicor, inc. makes no warranty of merchantability or fitness for any purpose. xicor, inc. reserves the right to discontinue prod uction and change specifications and prices at any time and without notice. xicor, inc. assumes no responsib ility for the use of any circuitry other than circuitry embodied in a xicor, inc. product. no o ther circuits, patents, or licenses are implied. trademark disclaimer: xicor and the xicor logo are registered trademarks of xicor, inc. autostore, direct write, block lock, serialflash, mps, biaslo ck and xdcp are also trademarks of xicor, inc. all others belong to their respective owners. u.s. patents xicor products are covered by one or more of the following u.s. patents: 4,326,134; 4,393,481; 4,404,475; 4,450,402; 4,486,769; 4,488,060; 4,520,461; 4,533,846; 4,599,706; 4,617,652; 4,668,932; 4,752,912; 4,829,482; 4,874,967; 4,883,976; 4,980,859; 5,012,132; 5,003,197; 5,023,694; 5,084, 667; 5,153,880; 5,153,691; 5,161,137; 5,219,774; 5,270,927; 5,324,676; 5,434,396; 5,544,103; 5,587,573; 5,835,409; 5,977,585. foreign patents and addition al patents pending. life related policy in situations where semiconducto r component failure may endanger life, system desi gners using this produc t should design the sy stem with appropriate error detection and correction, redundancy and back-up features to prevent such an occurrence. xicor?s products are not authorized for use in critical components in life support devices or systems. 1. life support devices or systems are devices or systems which, (a ) are intended for surgical impl ant into the body, or (b) sup port or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to res ult in a significant injury to the user. 2. a critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. ?xicor, inc. 2004 patents pending rev 1.6 6/22/04 www.xicor.com X93256 tssop packaging information note: all dimensions in inches (in parentheses in millimeters) 14-lead plastic, tssop, package code v14 see detail ?a? .031 (.80) .041 (1.05) .169 (4.3) .177 (4.5) .252 (6.4) bsc .025 (.65) bsc .193 (4.9) .200 (5.1) .002 (.05) .006 (.15) .041 (1.05) .0075 (.19) .0118 (.30) 0 - 8 .010 (.25) .019 (.50) .029 (.75) gage plane seating plane detail a (20x)
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