general description the max5460?ax5468 linear-taper digital potentiome-ters perform the same function as a mechanical poten- tiometer or a variable resistor. these devices consist of a fixed resistor and a wiper contact with 32-tap points that are digitally controlled through a 2-wire serial interface. the max5462/max5465/max5468 are configured as potentiometers. the rest of the devices in this family are configured as variable resistors. see pin configurations for part functionality.three resistance values are available: 10k ? (max5466/ max5467/max5468), 50k ? (max5463/max5464/ max5465), and 100k ? (max5460/ max5461/max5462). the max5460?ax5465 (100k ? and 50k ? ) are avail- able in space-saving 5-pin and 6-pin sc70 packages.the max5466/max5467/max5468 (10k ? ) are available in 5-pin and 6-pin sot23 packages. applications lcd screen adjustmentvolume control mechanical potentiometer replacement gain adjustment line impedance matching features ? miniature sc70 and sot23 packages ? 0.3a ultra-low supply current ? +2.7v to +5.5v single-supply operation ? glitchless switching between resistor taps ? power-on reset to midscale ? 2-wire up/down serial interface ? 10k ? , 50k ? , and 100k ? resistance values max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers ________________________________________________________________ maxim integrated products 1 top view gnd cs u/d 15 h v dd max5460max5463 max5466 sot23, sc70 234 gnd cs u/d 16 h v dd max5461max5464 max5467 sot23, sc70 234 l 5 gnd cs u/d 16 h v dd max5462max5465 max5468 sot23, sc70 234 w 5 pin configurations ordering information 19-1956; rev 3; 11/05 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. functional diagram appears at end of data sheet. part pin-package top mark r (k ) pkg code max5460 exk 5 sc70 aca 100 x5-1 max5461 ext 6 sc70 aap 100 x6s-1 max5462 ext 6 sc70 aaq 100 x6s-1 max5463 exk 5 sc70 acb 50 x5-1 max5464 ext 6 sc70 aar 50 x6s-1 max5465 ext 6 sc70 aas 50 x6s-1 max5466 euk 5 sot23 adqq 10 u5-1 max5467 eut 6 sot23 aarh 10 u6-1 max5468 eut 6 sot23 aari 10 u6-1 fleapot is a trademark of maxim integrated products inc. note: all devices operate over the -40? to +85? temperature range. downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics(v dd = +2.7v to +5.5v, v h = v dd , v l = 0, t a = -40? to +85?. typical values are at v dd = +2.7v, t a = +25?, 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. v dd to gnd ..............................................................-0.3v to +6v all other pins to gnd.................................-0.3v to (v dd + 0.3)v input and output latch-up immunity.............................?00ma maximum continuous current into h, l, and w max5460/max5461/max5462 (100k ? ) .......................?.6ma max5463/max5464/max5465 (50k ? ) .........................?.3ma max5466/max5467/max5468 (10k ? ) .........................?.3ma continuous power dissipation (t a = +70?) 5-pin sc70 (derate 3.1mw/? above t a = +70?) ..........247mw 5-pin sot23 (derate 7.1mw/? above t a = +70?)........571mw 6-pin sc70 (derate 3.1mw/? above t a = +70?) ..........245mw 6-pin sot23 (derate 8.7mw/? above t a = +70?).....695.7mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? soldering temperature (soldering, 10s) ..........................+300? parameter symbol conditions min typ max units dc performance resolution 32 taps max5460/max5461/max5462 75 100 125 max5463/max5464/max5465 37.5 50 62.5 end-to-end resistance max5466/max5467/max5468 7.5 10 12.5 k end-to-end resistance tempco tc r 35 ppm/ c ratiometric resistance tempco 5 ppm/ c integral nonlinearity inl 0.5 1 lsb differential nonlinearity dnl 1 lsb full-scale error 0.1 lsb zero-scale error 1 lsb max5462/max5465 600 1200 wiper resistance r w max5468 160 240 digital inputs input high voltage v ih 0.7 x v dd v input low voltage v il 0.3 x v dd v timing characteristics (figures 1, 2) u/ d mode to cs setup t cu 25 ns cs to u/ d step setup t ci 50 ns cs to u/ d step hold t ic 25 ns u/ d step low period t il 25 ns u/ d step high period t ih 25 ns up/down toggle rate (note 1) f toggle 1 mhz 100k var i ab l e r esi stor confi g ur ati on, c l = 10p f1 output settling time (note 2) t settle 100k p otenti om eter confi g ur ati on, c l = 10p f 0.25 ? downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers _______________________________________________________________________________________ 3 0 200100 400300 600500 700 02 . 0 1.0 3.0 4.0 0.5 2.5 1.5 3.5 4.5 5.0 wiper resistance vs. wiper voltage (max5460?ax5465) max5460 toc01 wiper voltage (v) wiper resistance ( ? ) v dd = +2.7v v dd = +5v 0 4020 8060 120100 140 180160 200 0 1.0 1.5 2.0 0.5 2.5 3.0 3.5 4.5 4.0 5.0 wiper resistance vs. wiper voltage (max5466/max5467/max5468) max5460 toc02 wiper voltage (v) wiper resistance ( ? ) v dd = +2.7v v dd = +5v -0.25 -0.15-0.20 -0.05-0.10 0.05 0 0.10 -40 10 -15 35 60 85 end-to-end resistance % change vs. temperature max5460 toc03 temperature ( c) end-to-end resistance % chnage 10k ? 50k ? , 100k ? 0 4020 8060 100 120 135791113 15 17 19 21 23 25 27 29 31 w-to-l resistance vs. tap position max5460 toc04 tap position resistance (k ? ) 100k ? 50k ? 10k ? 0.00 0.150.10 0.05 0.20 0.25 0.30 0.35 0.40 0.45 0.50 -40 10 - 1 5 3 56 08 5 supply current vs. temperature max5460 toc05 temperature ( c) current ( a) v dd = +5v v dd = +2.7v u/d 2v/div output w 100mv/div 200ns/div tap-to-tap switching transient (max5460) max5460 toc06 typical operating characteristics (t a = +25?, unless otherwise noted.) note 1: up/down toggle rate: note 2: typical settling times are dependent on end-to-end resistance. note 3: supply current taken while changing wiper tap, f toggle = 1mhz. note 4: supply current taken while wiper position is fixed. f t toggle settle = 1 electrical characteristics (continued)(v dd = +2.7v to +5.5v, v h = v dd , v l = 0, t a = -40? to +85?. typical values are at v dd = +2.7v, t a = +25?, unless otherwise noted.) parameter symbol conditions min typ max units power supplies supply voltage v dd 2.7 5.5 v active supply current (note 3) i dd 25 ? standby supply current (note 4) i sd v dd = +5v 0.3 1 a downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers 4 _______________________________________________________________________________________ typical operating characteristics (continued) (t a = +25?, unless otherwise noted.) pin description pin max5460max5463 max5466 max5461max5464 max5467 max5462max5465 max5468 name function 111v dd power supply 2 2 2 gnd ground 333u / d up/ down control input. with cs low, a low-to-high transition increments or decrements the wiper position. 444 cs chip select input. a high-to-low cs transition determines the mode: increment if u/ d is high, or decrement if u/ d is low. 5 6 6 h high terminal of resistor 5 l low terminal of resistor 5 w wiper terminal of resistor -0.10 0 -0.05 0.100.05 0.15 0.20 01 5 2 0 510 2530 r-inl error vs. input code (50k ? ) max5460 toc10 input code (decimal) r-inl lsb r-dnl error vs. input code (10k ? ) max5460 toc11 -0.25 -0.20 -0.10-0.15 0.05 0.10 0 -0.05 0.15 r-dnl lsb 01 0 1 5 5 20 25 30 input code (decimal) -0.15 -0.05-0.10 0.100.05 0 0.250.20 0.15 0.30 01 0 1 5 5 202530 r-inl error vs. input code (10k ? ) max5460 toc12 input code (decimal) r-inl (lsb) -0.10 -0.06-0.08 0 -0.02-0.04 0.060.04 0.02 0.08 01 0 1 5 5 202530 r-dnl error vs. input code (100k ? ) max5460 toc07 input code (decimal) r-dnl (lsb) -0.10 -0.04-0.06 -0.08 0 -0.02 0.080.06 0.04 0.02 0.10 0 5 10 15 20 25 30 r-inl error vs. input code (100k ? ) max5460 toc08 input code (decimal) r-inl (lsb) -0.14 -0.10-0.12 -0.04-0.06 -0.08 0.02 0 -0.02 0.04 01 0 1 5 52 0 2 5 3 0 r-dnl error vs. input code (50k ? ) max5460 toc09 input code (decimal) r-dnl (lsb) downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers _______________________________________________________________________________________ 5 detailed description the max5460?ax5468 consist of a fixed resistor and awiper contact with 32-tap points that are digitally con- trolled through a 2-wire serial interface. three resistance values are available: 10k ? (max5466/max5467/ max5468), 50k ? (max5463/max5464/max5465), and 100k ? (max5460/max5461/max5462). the max5462/ max5465/max5468 are designed to oper- ate as potentiometers. in this configuration, the low termi-nal of the resistor array is connected to ground (pin 2). the max5461/ max5464/max5467 perform as variable resistors. in these devices, the wiper terminal and highterminal of the resistor array are connected at pin 5. the max5460/max5463/max5466 are similar variable resistors, except the low terminal is connected to ground (pin 2). digital interface operation the max5460?ax5468 have two modes of operationwhen the serial interface is active: increment and decrement mode. the serial interface is only active when cs is low. the cs and u/ d inputs control the position of the wiper along the resistor array. when cs transitions from high to low, the part will go into increment mode if u/ d is high, and into decrement mode if u/ d is low. once the mode is set, the device will remain in that mode until cs goes high again. a low-to-high transition at the u/ d pin will incre- ment or decrement the wiper position depending on thecurrent mode (figures 1 and 2). when the cs input transitions to high (serial interface inactive), the value of the counter is stored and thewiper position is maintained. note that when the wiper reaches the maximum (or mini- mum) tap position, the wiper will not wrap around to the minimum (or maximum) position. cs u/d w note: "w" is not a digital signal. it represents wiper transitions. t cu t il t ih t settle t ic t ci t settle figure 1. serial interface timing diagram, increment mode cs u/dw t cu t il t ih t ic t settle t ci t settle note: "w" is not a digital signal. it represents wiper transitions. figure 2. serial interface timing diagram, decrement mode downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers 6 _______________________________________________________________________________________ power-on reset all parts in this family feature power-on reset (por) cir-cuitry that sets the wiper position to midscale at power- up. by default, the chip is in the increment mode. applications information the ma x5460?ax5468 are intended for circuits requiring digitally controlled adjustable resistance,such as lcd contrast control, where voltage biasing adjusts the display contrast. controlling a switch-mode lcd bias generator figure 3 shows an application where the variable resis-tor is used with a max1771 to make an adjustable posi- tive lcd-bias circuit. the output of the max1771 is a positive voltage that is digitally controlled through the max5461/max5464/max5467. similarly, figure 4 shows the application of the variable resistor in a digi- tally controlled negative lcd-bias circuit along with the max774/max775/max776. alternative positive lcd bias control alternatively, use an op amp to provide buffering andgain to the output of the max5462/max5465/max5468. connect the mechanical potentiometer to the positive input of a noninverting op amp (figure 5) to select a portion of the input signal by digitally controlling the wiper terminal. figure 6 shows a similar circuit for the max5461/max5464/max5467. adjustable gain figure 7 shows how to use the variable resistor to digi-tally adjust the gain of a noninverting op amp configura- tion. connect the max5461/max5464/max5467 in series with a resistor to ground to form the adjustablegain control of a noninverting amplifier. th e max5460 max5468 have a low 5ppm/? ratiometric tempco that allows for a very stable adjustable gain configurationover temperature. figure 3. adjustable positive lcd bias figure 4. adjustable negative lcd bias max774max775 max776 out v+ shdn cs fb ext gnd p 7 8 c20.1 f r30.07 ? r1 r2 r var c1 150 f 6 5 2 3 1 ref 4 q1si9435 1n5822/mbr340 l1 22 h c4 * v in c30.1 f v out * max774 = 330 f, 10v max775/max776 = 120 f, 20v v out(max) = r2 , v out(min) = r2 v ref r1 v ref r1 + r var v ref - v fb 5 a (for 2% gain-setting accuracy) r1 + r var max5461max5464 max5467 max1771 v in = 5v refshdn agnd gnd n mtd20n03hdl 7 ext cs fb l1 22 h d1 1n5817-22 c4 300 f c5 c3 0.1 f 54 6 18 3 2 v+ c1 68 f v out = 12v at 0.5a r2 r sense 40m ? c20.1 f v ref = 1.5v r1 r var v out(max) = r2 + 1 v ref r1 v out(min) = ( r2 ) + 1 v ref r1 + r var(max) max5461max5464 max5467 downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers _______________________________________________________________________________________ 7 30v w l h +5v v out max5462max5465 max5468 figure 5. positive lcd bias control 30v l h +5v v out max5461max5464 max5467 figure 6. positive lcd bias control v cc l h v in a) b) v out v cc l h w v in v out max5461max5464 max5467 max5462max5465 max5468 figure 7. adjustable gain circuit downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers 8 _______________________________________________________________________________________ chip information transistor count: 792 up/dn counter v dd gnd cs h l w u/d 32-position decoder max5460?ax5468 functional diagram downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers _______________________________________________________________________________________ 9 sc70, 5l.eps package outline, 5l sc70 21-0076 1 1 c sot-23 5l .eps e 1 1 21-0057 package outline, sot-23, 5l package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) downloaded from: http:///
max5460?ax5468 32-tap fleapot , 2-wire digital potentiometers 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. 10 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2005 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. 6lsot.eps package outline, sot 6l body 21-0058 1 1 g sc70, 6l.eps package outline, 6l sc70 21-0077 1 1 c package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) downloaded from: http:///
|
