precision air-core tach/speedo driver with separate function generator input features 1 package option 20 lead pdip cs4101 1 cp+ 2 3 4 5 6 7 8 sq out freq in bias gnd gnd nc cos+ 16 15 14 13 12 11 10 cp- f/v out v reg nc gnd gnd nc sin+ 9 cos- sin- 17 18 v cc f gen 19 20 cs4101 description block diagram april, 2001 - rev. 5 on semiconductor 2000 south county trail, east greenwich, ri 02818 tel: (401)885?600 fax: (401)885?786 n. american technical support: 800-282-9855 web site: www.onsemi.com absolute maximum ratings archive device not recommended for new design the cs4101 is specifically designed for use with air-core meter move- ments. the ic provides all the func- tions necessary for an analog tachometer or speedometer. the cs4101 takes a speed sensor input and generates sine and cosine relat- ed output signals to differentially drive an air-core meter. many enhancements have been added over industry standard tachometer drivers such as the cs289 or lm1819. the output uti- lizes differential drivers which elim- inates the need for a zener reference and offers more torque. the device withstands 60v transients which decreases the protection circuitry required. the device is also more precise than existing devices allow- ing for fewer trims and for use in a speedometer. absolute maximum ratings supply voltage (<100ms pulse transient) .........................................v cc = 60v (continuous)..............................................................v cc = 24v operating temperature .............................................................?0? to +105? storage temperature..................................................................?0? to +165? junction temperature .................................................................?0? to+150? esd (human body model) .............................................................................4kv lead temperature soldering wave solder(through hole styles only).............10 sec. max, 260? peak sine- sine+ gnd v reg f/v out sine output cos output v reg 7.0v v cc cos - cos + gnd gnd freq in sq out cp+ input comp. + + gnd cp- voltage regulator + + high voltage protection charge pump bias func. gen. f gen + + direct sensor input high output torque low pointer flutter high input impedance overvoltage protection block diagram
2 electrical characteristics: -40? t a 85?, 8.5v v cc 15v unless otherwise specified. parameter test conditions min typ max unit cs4101 supply voltage section i cc supply current v cc = 16v, -40?, no load 50 125 ma v cc normal operation range 8.5 13.1 16.0 v input comparator section positive input threshold 2.4 3.4 4.4 v input hysteresis 200 400 mv input bias current * 0v v in 8v -10 -80 a input frequency range 0 20 khz input voltage range in series with 1k ? -1 v cc v output v sat i cc = 10ma 0.15 0.40 v output leakage v cc = 7v 10 a low v cc disable threshold 7.0 8.0 8.5 v logic 0 input voltage 2.4 v *note: input is clamped by an internal 12v zener. voltage regulator section output voltage 6.25 7.00 7.50 v output load current 10 ma output load regulation 0 to 10 ma 10 50 mv output line regulation 8.5v v cc 16v 20 150 mv power supply rejection v cc = 13.1v, 1vp/p 1khz 34 46 db charge pump section inverting input voltage 1.5 2.0 2.5 v input bias current 40 150 na v bias input voltage 1.5 2.0 2.5 v non invert. input voltage i in = 1ma 0.7 1.1 v linearity* @ 0, 87.5, 175, 262.5, + 350hz -0.10 0.28 +0.70 % f/v out gain @ 350hz, c t = 0.0033 f, r t = 243k ? 7 10 13 mv/hz norton gain, positive i in = 15 a 0.9 1.0 1.1 i/i norton gain, negative i in = 15 a 0.9 1.0 1.1 i/i *note: applies to % of full scale (270?. function generator section: -40 t a 85?, v cc = 13.1v unless otherwise noted. differential drive voltage 8.5v v cc 16v 5.5 6.5 7.5 v (v cos + - v cos -) = 0 differential drive voltage 8.5v v cc 16v 5.5 6.5 7.5 v (v sin + - v sin -) = 90 differential drive voltage 8.5v v cc 16v -7.5 -6.5 -5.5 v (v cos + - v cos -) = 180 differential drive voltage 8.5v v cc 16v -7.5 -6.5 -5.5 v (v sin + - v sin -) = 270 differential drive current 8.5v v cc 16v 33 42 ma zero hertz output angle -1.5 0.0 1.5 deg function generator error * v cc = 13.1v -2 0 +2 deg reference figures 1,2,3,4 = 0 to 305 * note: deviation from nominal per table 1 after calibration at 0 and 270?
3 package lead # lead symbol function cs4101 electrical characteristics: -40? t a 85?, 8.5v v cc 15v unless otherwise specified. parameter test conditions min typ max unit function generator section: continued function generator error 13.1v v cc 16v -2.5 0 +2.5 deg function generator error 13.1v v cc 11v -1 0 +1 deg function generator error 13.1v v cc 9v -3 0 +3 deg function generator error 25? t a 80? -3 0 +3 deg function generator error 25? t a 105? -5.5 0 +5.5 deg function generator error ?0? t a 25? -3 0 +3 deg function generator gain t a = 25? vs f/v out 60 77 95 ?v package lead description typical performance characteristics 0 45 90 135 180 225 270 315 output voltage (v) degrees of deflection ( ) 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 cos sin 045 90 135 180 225 270 315 f/v output (v) frequency/output angle ( ) 7 6 5 4 3 2 1 0 figure 2: charge pump output voltage vs output angle figure 1: function generator output voltage vs degrees of deflection f/v out = 2.0v + 2 freq c t r t (v reg - 0.7) 20l 1 cp+ positive input to charge pump. 2sq out buffered square wave output signal. 3 freq in speed or rpm input signal. 4 bias test point or zero adjustment. 5, 6, 15, 16 gnd ground connections. 7, 14, 17 nc no connection. 8 cos+ positive cosine output signal. 9 cos- negative cosine output signal. 10 v cc ignition or battery supply voltage. 11 f gen function generator input signal. 12 sin- negative sine output signal. 13 sin+ positive sine output signal. 18 v reg voltage regulator output. 19 f/v out output voltage proportional to input signal frequency. 20 cp- negative input to charge pump.
4 typical performance characteristics continued cs4101 nominal angle vs. ideal angle (after calibrating at 180? +7v ?v (v cos+ ) - (v cos- ) 7v angle -7v (v sine+ ) - (v sine- ) ] v sin+ ?v sin- v cos+ ?v cos- = arctan [ -1.50 deviation ( ) 0 45 90 135 180 225 270 315 -1.25 -1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00 1.25 1.50 theoretical angle ( ) figure 4: nominal output deviation figure 3: output angle in polar form ideal angle (degrees) nominal angle (degrees) 0 5 10 15 20 25 30 35 40 45 1 5 9 13 17 21 25 29 33 37 41 45 ideal degrees nominal degrees 00 1 1.09 2 2.19 3 3.29 4 4.38 5 5.47 6 6.56 7 7.64 8 8.72 9 9.78 10 10.84 11 11.90 12 12.94 13 13.97 14 14.99 15 16.00 16 17.00 17 17.98 18 18.96 19 19.92 20 20.86 21 21.79 22 22.71 23 23.61 24 24.50 25 25.37 26 26.23 27 27.07 28 27.79 29 28.73 30 29.56 31 30.39 32 31.24 33 32.12 34 33.04 35 34.00 36 35.00 37 36.04 38 37.11 39 38.21 40 39.32 41 40.45 42 41.59 43 42.73 44 43.88 45 45.00 50 50.68 55 56.00 60 60.44 65 64.63 70 69.14 75 74.00 80 79.16 85 84.53 90 90.00 95 95.47 100 100.84 105 106.00 110 110.86 115 115.37 120 119.56 125 124.00 130 129.32 135 135.00 140 140.68 145 146.00 150 150.44 155 154.63 160 159.14 165 164.00 170 169.16 175 174.33 180 180.00 185 185.47 190 190.84 195 196.00 200 200.86 205 205.37 210 209.56 215 214.00 220 219.32 225 225.00 230 230.58 235 236.00 240 240.44 245 244.63 250 249.14 255 254.00 260 259.16 265 264.53 270 270.00 275 275.47 280 280.84 285 286.00 290 290.86 295 295.37 300 299.21 305 303.02 ideal nominal ideal nominal ideal nominal ideal nominal ideal nominal ideal nominal degrees degrees degrees degrees degrees degrees degrees degrees degrees degrees degrees degrees table 1: function generator output nominal angle vs. ideal angle (after calibrating at 270? note: temperature, voltage and nonlinearity not included. note: temperature, voltage and nonlinearity not included.
5 cs4101 the cs4101 is specifically designed for use with air-core meter movements. it includes an input comparator for sensing an input signal from an ignition pulse or speed sensor, a charge pump for frequency to voltage conver- sion, a bandgap voltage regulator for stable operation, and a function generator with sine and cosine amplifiers to differentially drive the motor coils. from the simplified block diagram of figure 5a, the input signal is applied to the freq in lead, this is the input to a high impedance comparator with a typical pos- itive input threshold of 3.4v and typical hysteresis of 0.4v. the output of the comparator, sq out , is applied to the charge pump input cp+ through an external capaci- tor c t . when the input signal changes state, c t is charged or discharged through r3 and r4. the charge accumulated on c t is mirrored to c 4 by the norton amplifier circuit comprising q1, q2 and q3. the charge pump output voltage, f/v out , ranges from 2v to 6.3v depending on the input signal frequency and the gain of the charge pump according to the formula: f/v out = 2.0v + 2 freq c t r t (v reg ?0.7v) r t is a potentiometer used to adjust the gain of the f/v output stage and give the correct meter deflection. the f/v output voltage is applied to the function generator input lead, f gen . an additional filter circuit can be added between f/v out and f gen to reduce needle flutter. the output voltage of the sine and cosine amplifiers are derived from the on-chip amplifier and function genera- tor circuitry. the various trip points for the circuit (i.e., 0? 90? 180? 270? are determined by an internal resistor divider, and the bandgap voltage reference. the coils are differentially driven, allowing bidirectional current flow in the outputs, thus providing up to 305 range of meter deflection. driving the coils differentially offers faster response time, higher current capability, higher output voltage swings, and reduced external component count. the key advantage is a higher torque output for the pointer. the output angle, , is equal to the f/v gain multiplied by the function generator gain: = a f/v a fg , where: a fg = 77 /v (typ) the relationship between input frequency and output angle is: = a fg 2 freq c t r t (v reg ?0.7v) or, = 970 freq c t r t the ripple voltage at the f/v converter? output is deter- mined by the ratio of c t and c4 in the formula: ? v = ripple voltage on the f/v output causes pointer or nee- dle flutter especially at low input frequencies. the response time of the f/v is determined by the time constant formed by r t and c4. increasing the value of c4 will reduce the ripple on the f/v output but will also increase the response time. an increase in response time causes a very slow meter movement and may be unac- ceptable for many applications. design example maximum meter deflection = 270 maximum input frequency = 350hz 1. select r t and c t = a gen ? f/v ? f/v = 2 freq c t r t (v reg ?0.7v) = 970 freq c t r t let c t = 0.0033 f, find r t r t = r t = 243k ? r t should be a 250k ? potentiometer to trim out any inac- curacies due to ic tolerances or meter movement pointer placement. 2. select r3 and r4 resistor r3 sets the output current from the voltage regu- lator. the maximum output current from the voltage reg- ulator is 10ma r 3 must ensure that the current does not exceed this limit. choose r3 = 3.3k ? the charge current for c t is: = 1.90ma c 1 must charge and discharge fully during each cycle of the input signal. time for one cycle at maximum frequen- cy is 2.85ms. to ensure that c t is discharged, assume that the (r3 + r4) c t time constant is less than 10% of the minimum input frequency pulse width. t = 285 s choose r4 = 1k ? . charge time: t = r3 c t = 3.3k ? 0.0033 f = 10.9 s discharge time: t = (r3 + r4)c t = 4.3k ? 0.0033 f = 14.2 s 3. determine c4 c4 is selected to satisfy both the maximum allowable rip- ple voltage and response time of the meter movement. c4 = with c4 = 0.47 f, the f/v ripple voltage is 44mv. figure 7 shows how the cs4101 and the cs-8441 are used to produce a speedometer and odometer circuit. c t (v reg ?0.7v) v ripple(max) v reg ?0.7v 3.3k ? 270 970 350hz 0.0033 f c t (v reg ?0.7v) c4 circuit description and application notes
6 cs4101 circuit description and application notes: continued + r t c4 cp + f/v out f to v 2.0v q2 q1 q3 0.25v cp+ r4 c t v c (t) + r3 v reg sq out q square 3.4v freq in t pw t-pw freq in i cp+ sq out v cc v reg 0 0 0 v cp+ figure 5a: partial schematic of input and charge pump figure 5b: timing diagram of freq in and i cp
7 speedometer/odometer or tachometer application 10 1 cp+ 2 3 4 5 6 7 8 sq out freq in gnd gnd sin+ cos+ nc 20 19 18 17 16 15 14 13 cp- f/v out v reg nc gnd gnd nc bias cs4101 c t r3 c3 c1 d2 r1 d1 + c4 r t cosine sine air core gauge 200 ? speedometer battery speedo input c2 r2 r4 cp+ 9 cos- v cc 12 11 sine- f gen c t r3 c3 c1 d2 r1 d1 + c4 r t cosine sine air core gauge 200 ? speedometer battery speedo input r2 r4 1 cs8441 c2 air core stepper motor 200 ? odometer 10 1 cp+ 2 3 4 5 6 7 8 sq out freq in gnd gnd sin+ cos+ nc 20 19 18 17 16 15 14 13 cp- f/v out v reg nc gnd gnd nc bias cs4101 cp+ 9 cos- v cc 12 11 sine- f gen cs4101 r1 - 3.9, 500mw r2 - 10k ? r3 - 3k ? r4 - 1k ? r t - trim resistor +/- 20 ppm/deg. c c1 - 0.1 f c2 - 1. stand alone speedo or tach "0" f 2. stand alone speedo or tach with return to zero, 2000 f 3. with cs-8441 application, 10 f c3 - 0.1 f c4 - 0.47 f c t - 0.0033 f, +/- 30 ppm/? d1 - 1a, 600 piv d2 - 50v, 500mw zener note 1: for 58% speed input t max 5/f max where t max = c t (r3+r4) f max = maximum speed input frequency note 1: the product of c t and r t have a direct effect on gain and therefore directly effect temperature compensation note 2: c4 range; 20pf to .2 f note 3: r4 range; 100k ? to 500k ? note 4: the ic must be protected from transients above 60v and reverse battery conditions note 5: additional filtering on the freq in lead may be required figure 6 figure 7
8 cs4101 part number description cs4101en20 20l pdip d lead count metric english max min max min 20 lead pdip 26.92 24.89 1.060 .980 ordering information thermal data 20l pdip r jc typ 25 ?/w r ja typ 65 ?/w package specification package dimensions in mm (inches) package thermal data plastic dip (n); 300 mil wide 0.39 (.015) min. 2.54 (.100) bsc 1.77 (.070) 1.14 (.045) d some 8 and 16 lead packages may have 1/2 lead at the end of the package. all specs are the same. .203 (.008) .356 (.014) ref: jedec ms-001 3.68 (.145) 2.92 (.115) 8.26 (.325) 7.62 (.300) 7.11 (.280) 6.10 (.240) .356 (.014) .558 (.022) on semiconductor and the on logo are trademarks of semiconductor components industries, llc (scillc). on semiconductor reserves the right to make changes without further notice to any products herein. for additional infor- mation and the latest available information, please contact your local on semiconductor representative. ?semiconductor components industries, llc, 2001
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