general description the max5160/max5161 linear-taper digital potentiome- ters perform the same function as a mechanical poten- tiometer or a variable resistor. they consist of a fixed resistor and a wiper contact with 32 tap points that are digitally controlled by three lines for the 8-pin max5160 or by two lines for the 6-pin max5161. these parts are ideal for applications requiring digitally controlled resistors. three resistance values are avail- able for each part type: 50k ? , 100k ? , and 200k ? . a nominal resistor temperature coefficient of 50ppm/? end-to-end and only 5ppm/? ratiometric makes the max5160 ideal for applications requiring a low-temper- ature-coefficient variable resistor, such as low-tempco, adjustable-gain circuit configurations. the max5160 is available in an 8-pin ?ax package, and the max5161 is available in a 6-pin sot23 pack- age. both devices are guaranteed over the extended- industrial temperature range (-40? to +85?). applications lcd screen adjustment volume control mechanical potentiometer replacement features 32 tap positions 50k ? , 100k ? , and 200k ? resistance values 400 ? wiper resistance 25% resistance tolerance 3-wire serial data input 1lsb dnl 0.5lsb inl 100na supply current +2.7v to +5.5v single-supply operation power-on reset: wiper goes to midscale (position 16) 2kv esd protection small-footprint packages 6-pin sot23 (max5161) 8-pin max (max5160) glitchless switching between the resistor taps max5160/max5161 low-power digital potentiometers ________________________________________________________________ maxim integrated products 1 1 2 3 4 8 7 6 5 v dd cs l w gnd h u/d inc max5160 max top view h u/d gnd 16 v dd 5 inc l max5161 sot23-6 2 34 up/dn counter v dd gnd cs h l w inc u/d position decoder max5160 max5161 functional diagram 19-1435; rev 2a; 2/01 part max5160 neua max5160meua pin- package 8 ?ax 8 ?ax pin configurations selector guide ordering information -40? to +85? -40? to +85? temp. range max5160leua -40? to +85? 8 ?ax max5161 nezt -40? to +85? 6 sot23 MAX5161MEZT -40? to +85? 6 sot23 max5161lezt -40? to +85? 6 sot23 r (k ? ) 200 100 50 200 100 50 for price, delivery, and to place orders, please contact maxim distribution at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part top mark r (k ? ) max5160 neua 200 max5160meua 100 max5160leua 50 max5161 nezt aaac 200 MAX5161MEZT aaab 100 max5161lezt aaaa 50
max5160/max5161 low-power digital potentiometers 2 _______________________________________________________________________________________ note 1: for the max5160, linearity is defined in terms of h to l code-dependent resistance. absolute maximum ratings electrical characteristics (v dd = +2.7v to +5.5v, v h = v dd , v l = 0, t a = t min to t max . typical values are at v dd = +5v, t a = +25 c, unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. v dd to gnd ..............................................................-0.3v to +6v cs , inc , u/ d to gnd ...............................................-0.3v to +6v h, l, w to gnd.......................................... -0.3v to (v dd + 0.3v) input and output latchup immunity ..............................200ma maximum continuous current into h, l, and w max516_ _ e_ _...............................................................1ma continuous power dissipation (t a = +70 c) 6-pin sot23 (derate 6.25mw/ c above +70 c)...........500mw 8-pin max (derate 4.1mw/ c above +70 c) ..............330mw operating temperature range .......................... -40 c to +85 c storage temperature range .............................-65 c to +150 c lead temperature (soldering, 10s) ................................+300 c max516_me_ _ max516_ne_ _ max516_le_ _ conditions ns 50 t di u/ d to inc setup ns 0 t id u/ d to inc hold ns 25 t ih inc high period ns 25 t il inc low period ns 0 t ic cs to inc hold time ns 25 t ci cs to inc setup time pf 5 input capacitance a 1 input leakage current v 0.3 ? v dd v il input low voltage v 0.7 ? v dd v ih input high voltage k ? 37.5 50 62.5 hl end-to-end resistance lsb 1/2 inl integral nonlinearity (note 1) % 3 resolution 75 100 125 150 200 250 ? 400 1700 r w wiper resistance lsb +0.1 zero-scale error lsb 1 dnl differential nonlinearity (note 1) ppm/ c 50 tc r end-to-end resistor tempco ppm/ c 5 ratiometric resistor tempco lsb -0.1 full-scale error units min typ max symbol parameter mhz 7 f imax inc frequency s 1 t iw wiper-settling time cs = inc = u/ d = v dd or gnd na 135 i dd supply current a 0.6 10 v 2.7 5.5 v dd supply voltage v dd = +5v v dd = +2.7v pf 10 c w wiper capacitance digital inputs timing characteristics (figure 6) power supplies dc performance
max5160/max5161 low-power digital potentiometers _______________________________________________________________________________________ 3 0 200 400 600 800 1,000 012345 wiper resistance vs. wiper voltage max5160/61 toc01 wiper voltage (v) wiper resistance ( ? ) r wmax = 574.0804 v dd = +2.7v v dd = +5v -0.16 -0.10 -0.12 -0.14 0 -0.02 -0.04 -0.06 -0.08 0.02 0.04 0.06 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 end-to-end resistance % change vs. temperature max5160/61 toc02 temperature ( c) end-to-end resistance % change 200k ? 200k ? 100k ? 50k ? 50k ? 100k ? 0 50 25 125 100 75 150 175 200 225 1 5 9 131721252933 end-to-end resistance vs. tap position max5160/61 toc03 tap position resistance (k ? ) 200k ? 0 20 10 50 40 30 60 70 80 90 100 110 1 5 9 131721252933 end-to-end resistance vs. tap position max5160/61 toc04 tap position resistance (k ? ) 100k ? typical operating characteristics (v dd = +5v, t a = +25 c, unless otherwise noted.) 0 10 5 25 20 15 30 35 40 45 50 1 5 9 131721252933 end-to-end resistance vs. tap position max5160/61 toc05 tap position resistance (k ? ) 50k ?
max5160/max5161 low-power digital potentiometers 4 _______________________________________________________________________________________ pin output w 50mv/div 0v inc 2v/div 0v 5 s/div tap-to-tap switching transient max5160/61 toc07 typical operating characteristics (continued) (v dd = +5v, t a = +25 c, unless otherwise noted.) 0 0.2 0.1 0.5 0.4 0.3 0.8 0.7 0.6 0.9 -40 0 20 -20 406080100 supply current vs. temperature max5160/61 toc06 temperature (?) supply current ( a) v dd = +5v v dd = +2.7v 1 inc wiper increment control input. with cs low, a high-to-low transition increments (u/ d high) or decrements (u/ d low) the wiper position. 2 u/ d up/down control input. with cs low, a high-to-low inc transition increments (u/ d high) or decrements (u/ d low) the wiper position. 3 h high terminal of resistor 4 gnd ground 8 v dd power supply 7 cs chip-select input. drive low to change the wiper position through inc and u/ d. 6 l low terminal of resistor 5 w wiper terminal of resistor pin description name function max5160 5 4 pin 2 3 6 1 max5161
max5160/max5161 low-power digital potentiometers _______________________________________________________________________________________ 5 detailed description the max5160/max5161 consist of resistor arrays with thirty-one resistive elements. thirty-two tap points are accessible to the wiper along the resistor string between h and l. logic inputs cs , u/ d , and inc determine the position of the wiper. with cs low and u/ d high, a high-to-low transition on inc increments the internal counter, increasing the resistance between w and l. when both cs and u/ d are low, a high-to-low inc transition decre ments the internal counter, decreas- ing the resistance between w and l. at either end (maximum or minimum positions), additional transitions in the direction of the end points will not change the counter value (the counter will not wrap around). the h and l terminals of the max5160 are similar to the two end terminals of a mechanical potentiometer. the tap w is equivalent to the variable tap (wiper) of the potentiometer. the max5161 is similar to the max5160 except that cs internally connects to ground and the wiper terminal (w) is shorted to the high terminal (h). the max5161 acts as a variable resistor (a potentiometer with the wiper and one end terminal shorted together). the max5160/max5161 feature power-on reset circuit- ry that sets the wiper position to midscale at power-up. applications information the max5160/max5161 are intended for circuits requiring digitally controlled adjustable voltage or adjustable gain, such as lcd contrast control, where voltage biasing adjusts the display contrast. controlling a switch-mode lcd bias generator figure 1 shows an application where the max5161 is used with a max1771 to make an adjustable positive lcd-bias circuit. the output of the max1771 is a posi- tive voltage that is digitally controlled through the max5160/max5161. similarly, figure 2 shows the application of the max5161 in a digitally controlled negative lcd-bias circuit along with the max774/ max775/max776. max1771 v in = 5v ref shdn agnd gnd n mtd20n03hdl 7 ext cs fb l1 22 h d1 1n5817-22 c4 300 f c5 c3 0.1 f 5 4 6 1 8 3 2 v+ c1 68 f v out = 12v at 0.5a r2 r sense 40m ? c2 0.1 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) max5161 figure 1. adjustable positive lcd bias max774 max775 max776 out v+ shdn cs fb ext gnd p 7 8 c2 0.1 f r3 0.07 ? r1 r2 r var c1 150 f 6 5 2 3 1 ref 4 q1 si9435 1n5822/ mbr340 l1 22 h c4 * v in c3 0.1 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 max5161 figure 2. adjustable negative lcd bias
max5160/max5161 alternative positive lcd bias control alternatively, use an op amp to provide buffering and gain to the output of the max5160/max5161. connect the max5160 to the positive input of a noninverting op amp (figure 3) to select a portion of the input signal by digitally controlling the wiper terminal. figure 4 shows a similar circuit for the max5161. adjustable gain figure 5 shows how to use the max5161 to digitally adjust the gain of a noninverting op amp configuration. connect the max5161 in series with a resistor to ground to form the adjustable gain control of a noninverting amplifier. the max5160/max5161 have a low 5ppm/ c ratiometric tempco that allows for a very stable adjust- able gain configuration over temperature. serial interface figure 6 is the serial-interface timing diagram. low-power digital potentiometers 6 _______________________________________________________________________________________ gain 6 30v w l h inc cs gnd +5v +5v v out v dd u/d max5160 figure 3. max5160 positive lcd bias control gain 6 30v l h gnd +5v +5v v out v dd inc u/d max5161 figure 4. max5161 positive lcd bias control v cc l h gnd v in +5v a) b) v out v dd inc u/d v cc l h w v in v out max5161 max5160 figure 5. adjustable gain circuit: a) max5161; b) max5160
chip information transistor count: 969 max5160/max5161 low-power digital potentiometers _______________________________________________________________________________________ 7 h + l h l l o l l o l r w o inc x u/ d xx-x cs h cs inc u/d w t ci t il t di t ih t ic t id t iw figure 6. serial-interface timing diagram truth table x = don? care o = previous state + = increment = decrement = high-to-low transition = low-to-high transition
max5160/max5161 low-power digital potentiometers 8 _______________________________________________________________________________________ package information 8lumaxd.eps
max5160/max5161 low-power digital potentiometers package information (continued) 6 lead thin sot23.eps maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 9 ? 2001 maxim integrated products printed usa is a registered trademark of maxim integrated products.
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