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? 2002-2012 microchip technology inc. ds21457d-page 1 tc7116/a/tc7117/a features: ? low temperature drift internal reference: - tc7116/tc7117 80 ppm/c, typ. - tc7116a/tc7117a 20 ppm/c, typ. ? display hold function ? directly drives lcd or led display ? zero reading with zero input ? low noise for stable display: - 2v or 200mv full scale range (fsr) ? auto-zero cycle eliminates need for zero ? adjustment potentiometer ? true polarity indication for precision null applications ? convenient 9v battery operation: (tc7116/tc7116a) ? high-impedance cmos differential inputs: 10 12 ? ? low-power operation: 10mw applications: ? thermometry ? bridge readouts: strain gauges, load cells, null detectors ? digital meters: voltage/current/ohms/power, ph ? digital scales, process monitors ? portable instrumentation device selection table general description: the tc7116a/tc7117a are 3-1/2 digit cmos analog- to-digital converters (adcs) containing all the active components necessary to construct a 0.05% resolution measurement system. seven-segment decoders, polarity and digit drivers, voltage reference, and clock circuit are integrated on-chip. the tc7116a drives liquid crystal displays (lcds) and includes a back- plane driver. the tc7117a drives common anode light emitting diode (led) displays directly with an 8ma drive current per segment. these devices incorporate a display hold (hldr) function. the displayed reading remains indefinitely, as long as hldr is held high. conversions continue, but output data display latches are not updated. the refer- ence low input (v ref -) is not available, as it is with the tc7106/7107. v ref - is tied internally to analog common in the tc7116a/7117a devices. the tc7116a/7117a reduces linearity error to less than 1 count. rollover error (the difference in readings for equal magnitude but opposite polarity input signals) is below 1 count. high-impedance differential inputs offer 1pa leakage current and a 10 12 ? input imped- ance. the 15 ? v p-p noise performance enables a ?rock solid? reading. the auto-zero cycle ensures a zero display reading with a 0v input. the tc7116a and tc7117a feature a precision, low drift internal reference, and are functionally identical to the tc7116/tc7117. a low drift external reference is not normally required with the tc7116a/tc7117a. package code package temperature range cpl 40-pin pdip 0 ? c to +70 ? c ijl 40-pin cerdip -25 ? c to +85 ? c ckw 44-pin pqfp 0 ? c to +70 ? c clw 44-pin plcc 0 ? c to +70 ? c 3-1/2 digit analog-to-digit al converters with hold
tc7116/a/tc7117/a ds21457d-page 2 ? 2002-2012 microchip technology inc. package type bp/ gnd 33 34 35 36 37 38 39 13 10 9 8 7 common v+ 18 19 20 21 23 24 ab 4 pol nc v in + nc v in - b2 6543 144 2 a 1 osc1 22 43 osc2 42 osc3 41 test 40 v ref + 25 26 27 28 f 3 e 3 g 3 a 3 c 3 g 2 32 14 c az 31 15 v buff 30 16 v int e 2 29 17 d 3 nc 11 12 nc c 2 d 2 f 2 a 2 b 3 tc7116clw tc7116aclw tc7117clw tc7117aclw tc7116cpl tc7116acpl tc7117cpl tc7117acpl v- c ref + c ref - b 1 c 1 d 1 f 1 g 1 e 1 bp/ gnd 27 28 29 30 31 32 33 7 4 3 2 1 nc tc7116ckw tc7116ackw tc7117ckw tc7117ackw 12 13 14 15 17 18 g 3 44 43 42 41 39 38 40 v ref + common 16 37 c az 36 v buff 35 v int 34 v- 19 20 21 22 d 3 26 8 25 9 24 10 23 11 v in + 5 6 c 3 osc3 test nc nc hldr d 2 c 2 b 2 a 2 f 2 e 2 nc osc2 osc1 v+ c ref + c ref - v in - a 3 g 3 pol ab 4 e 3 f 3 b 3 d 1 c 1 b 1 a 1 f 1 g 1 e 1 40-pin pdip 40-pin cerdip 44-pin plcc 44-pin pqfp 1 2 3 4 osc1 5 6 7 8 9 10 11 12 test v ref + common c az hldr d 2 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 c 2 b 2 a 2 f 2 e 2 d 3 b 3 f 3 e 3 ab 4 (minus sign) (minus sign) 10's 100's 1000's (tc7116/7117) (tc7116a/tc7117a) (tc7116/7117) (tc7116a/tc7117a) 100's osc2 osc3 v+ c ref + c ref - v in + v in - v buff v int v- g 2 c 3 a 3 g 3 bp/gnd pol d 1 c 1 b 1 a 1 f 1 g 1 e 1 1's hldr tc7116ijl tc7116aijl tc7117ijl tc7117aijl 1 2 3 4 osc1 5 6 7 8 9 10 11 12 test v ref + common c az hldr d 2 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 c 2 b 2 a 2 f 2 e 2 d 3 b 3 f 3 e 3 ab 4 10's 100's 1000's 100's osc2 osc3 v+ c ref + c ref - v in + v in - v buff v int v- g 2 c 3 a 3 g 3 bp/gnd pol d 1 c 1 b 1 a 1 f 1 g 1 e 1 1's note 1: nc = no internal connection. 2: pins 9, 25, 40 and 56 are connected to the die substrate. the potential at these pins is approximately v+. no external connections should be made.
? 2002-2012 microchip technology inc. ds21457d-page 3 tc7116/a/tc7117/a typical application v ref + tc7116/a 9v v ref 33 34 24k 1k 31 29 36 39 38 40 0.47 f 0.1 f v- osc1 osc3 osc2 to analog common (pin 32) 3 conversions per second c osc 100k 47k 0.22 f 0.01 f analog input + ? c ref - c ref + v in + v in - analog common v int v buff c az 20 21 35 segment drive 2?19 22?25 pol bp/gnd v+ minus sign backplane drive 28 r osc 100pf lcd display (tc7116/7116a) or common anode led display (tc7117/7117a) 1m 27 30 32 hldr display hold 100mv 1 26 tc7117/a +
tc7116/a/tc7117/a ds21457d-page 4 ? 2002-2012 microchip technology inc. 1.0 electrical characteristics absolute maximum ratings* supply voltage: tc7116/tc7116a (v+ to v-) ...........................15v tc7117/tc7117a (v+ to gnd) .......................+6v v- to gnd.........................................................-9v analog input voltage (either input) (note 1) ... v+ to v- reference input voltage (either input) ............ v+ to v- clock input: tc7116/tc7116a............................... test to v+ tc7117/tc7117a.................................gnd to v+ package power dissipation; t a ? 70c (note 2) 40-pin cdip ................................................2.29w 40-pin pdip ................................................1.23w 44-pin plcc ...............................................1.23w 44-pin pqfp ...............................................1.00w operating temperature: c (commercial) device ................... 0c to +70c i (commercial) device.................... 0c to +70c storage temperature..........................-65c to +150c *stresses above those listed under ?absolute 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 above those indicated in the operation sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. table 1-1: tc7116/a and tc7117/a electrical specifications electrical characteristics: unless otherwise noted, specifications apply to both the tc7116/a and tc7117/a at t a = 25c, f clock = 48khz. parts are tested in the circuit of the typical operating circuit. symbol parameter min typ max unit test conditions z ir zero input reading ? 0 ? digital reading v in = 0v full scale = 200mv ratiometric reading 999 999/1000 1000 digital reading v in = v ref v ref = 100mv r/o rollover error (difference in reading for equal positive and negative readings near full scale) -1 0.2 +1 counts v in - = + v in + ? 200mv or ?? 2v linearity (maximum deviation from best straight line fit) -1 0.2 +1 counts full scale = 200mv or 2v cmrr common mode rejection ratio (note 3) ?50? ? v/v v cm = 1v, v in = 0v full scale = 200mv e n noise (peak to peak 95% of time) ? 15 ? ? vv in = 0v full scale = 200mv i l leakage current at input ? 1 10 pa v in = 0v zero reading drift ? 0.2 1 ? v/c v in = 0v ?c? device = 0c to +70c ?1.02 ? v/c ?i? device = -25c to +85c note 1: input voltages may exceed the supply voltages provided the input current is limited to 100 ? a. 2: dissipation rating assumes device is mounted with all leads soldered to printed circuit board. 3: refer to ?differential input? discussion. 4: backplane drive is in phase with segment drive for ?off? segment, 180 out of phase for ?on? segment. frequency is 20 times conversion rate. average dc component is less than 50mv. 5: the tc7116/tc7116a logic inputs have an internal pull-down resistor connected from hldr, pin 1 to test, pin 37. the tc7117/tc7117a logic inputs have an internal pull-down resistor connected from hldr, pin 1 to gnd, pin 21.
? 2002-2012 microchip technology inc. ds21457d-page 5 tc7116/a/tc7117/a tc sf scale factor temperature coefficient ? 1 5 ppm/c v in = 199mv, ?c? device = 0c to +70c (ext. ref = 0ppmc) ? ? 20 ppm/c ?i? device = -25c to +85c input resistance, pin 1 30 70 ? k ? (note 5) v il, pin 1 ? ? test + 1.5 v tc7116/a only v il, pin 1 ? ? gnd + 1.5 v tc7117/a only v ih, pin 1 v + - 1.5 ? ? v both i dd supply current (does not include led current for tc7117/a) ?0.81.8mav in = 0v v c analog common voltage (with respect to positive supply) 2.4 3.05 3.35 v 25k ? between common and positive supply v ctc temperature coefficient of analog common (with respect to positive supply) ?? 20 80 ? 50 ? ? ppm/c ppm/c ?c? device: 0c to ? +70c tc7116a/tc7117a tc7116/tc7117 v sd tc7116/tc7117a only peak to peak segment drive voltage 4 5 6 v v+ to v- = 9v (note 4) v bd tc7116a/tc7116a only peak to peak backplane drive voltage 4 5 6 v v+ to v- = 9v (note 4) tc7117/tc7117a only segment sinking current (except pin 19) 5 8 ? ma v+ = 5.0v segment voltage = 3v tc7117/tc7117a only segment sinking current (pin 19 only) 10 16 ? ma v+ = 5.0v segment voltage = 3v table 1-1: tc7116/a and tc7117/a electrical specifications (continued) electrical characteristics: unless otherwise noted, specifications apply to both the tc7116/a and tc7117/a at t a = 25c, f clock = 48khz. parts are tested in the circuit of the typical operating circuit. symbol parameter min typ max unit test conditions note 1: input voltages may exceed the supply voltages provided the input current is limited to 100 ? a. 2: dissipation rating assumes device is mounted wit h all leads soldered to printed circuit board. 3: refer to ?differential input? discussion. 4: backplane drive is in phase with segment drive for ?off? segment, 180 out of phase for ?on? segment. frequency is 20 times conversion rate. average dc component is less than 50mv. 5: the tc7116/tc7116a logic inputs have an internal pull-down resistor connected from hldr, pin 1 to test, pin 37. the tc7117/tc7117a logic inputs have an internal pull-down resistor connected from hldr, pin 1 to gnd, pin 21.
tc7116/a/tc7117/a ds21457d-page 6 ? 2002-2012 microchip technology inc. 2.0 pin descriptions the descriptions of the pins are listed in table 2-1. table 2-1: pin function table pin number (40-pin pdip) (40-pin cerdip) pin number (44-pin pqfp) symbol description 1 8 hldr hold pin, logic 1 holds present display reading. 29d 1 activates the d section of the units display. 310c 1 activates the c section of the units display. 411b 1 activates the b section of the units display. 512a 1 activates the a section of the units display. 613f 1 activates the f section of the units display. 714g 1 activates the g section of the units display. 815e 1 activates the e section of the units display. 916d 2 activates the d section of the tens display. 10 17 c 2 activates the c section of the tens display. 11 18 b 2 activates the b section of the tens display. 12 19 a 2 activates the a section of the tens display. 13 20 f 2 activates the f section of the tens display. 14 21 e 2 activates the e section of the tens display. 15 22 d 3 activates the d section of the hundreds display. 16 23 b 3 activates the b section of the hundreds display. 17 24 f 3 activates the f section of the hundreds display. 18 25 e 3 activates the e section of the hundreds display. 19 26 ab 4 activates both halves of the 1 in the thousands display. 20 27 pol activates the negative polarity display. 21 28 bp/ gnd lcd backplane drive output (tc7116/tc7116a). digital ground (tc7117/tc7117a). 22 29 g 3 activates the g section of the hundreds display. 23 30 a 3 activates the a section of the hundreds display. 24 31 c 3 activates the c section of the hundreds display. 25 32 g 2 activates the g section of the tens display. 26 34 v- negative power supply voltage. 27 35 v int integrator output. connection point for integration capacitor. see section 4.3 ?integrating capacitor? , integrating capacitor for more details. 28 36 v buff integration resistor connection. use a 47k ? resistor for a 200mv full scale range and a 470k ? resistor for 2v full scale range. 29 37 c az the size of the auto-zero capacitor influences system noise. use a 0.47 ? f capacitor for 200mv full scale, and a 0.047 ? f capacitor for 2v full scale. see section 4.1 ?auto-zero capacitor? , auto-zero capacitor for more details. 30 38 v in - the analog low input is connected to this pin. 31 39 v in + the analog high input signal is connected to this pin. 32 40 common this pin is primarily used to set the analog common mode voltage for battery operation, or in systems where the input signal is referenced to the power sup- ply. it also acts as a reference voltage source. see section 3.1.6 ?analog com- mon? , analog common for more details. 33 41 c ref - see pin 34.
? 2002-2012 microchip technology inc. ds21457d-page 7 tc7116/a/tc7117/a 34 42 c ref +a 0.1 ? f capacitor is used in most applications. if a large common mode voltage exists (for example, the v in - pin is not at analog common), and a 200mv scale is used, a 1 ? f capacitor is recommended and will hold the rollover error to 0.5 count. 35 43 v+ positive power supply voltage. 36 44 v ref + the analog input required to generate a full scale output (1999 counts). place 100mv between pins 32 and 36 for 199.9mv full scale. place 1v between pins 35 and 36 for 2v full scale. see section 4.6 ?reference voltage? , refer- ence voltage. 37 3 test lamp test. when pulled high (to v+), all segments will be turned on and the dis- play should read -1888. it may also be used as a negative supply for externally generated decimal points. see section 3.1.7 ?test? , test for additional infor- mation. 38 4 osc3 see pin 40. 39 6 osc2 see pin 40. 40 7 osc1 pins 40, 39, 38 make up the oscillator section. for a 48khz clock (3 readings per section), connect pin 40 to the junction of a 100k ? resistor and a 100pf capaci- tor. the 100k ? resistor is tied to pin 39 and the 100pf capacitor is tied to pin 38. table 2-1: pin function table (continued) pin number (40-pin pdip) (40-pin cerdip) pin number (44-pin pqfp) symbol description
tc7116/a/tc7117/a ds21457d-page 8 ? 2002-2012 microchip technology inc. 3.0 detailed description (all pin designations refer to 40-pin pdip.) 3.1 analog section figure 3-1 shows the block diagram of the analog sec- tion for the tc7116/tc7116a and tc7117/tc7117a. each measurement cycle is divided into three phases: (1) auto-zero (az), (2) signal integrate (int), and (3) reference integrate (ref), or de-integrate (de). 3.1.1 auto-zero phase high and low inputs are disconnected from the pins and internally shorted to analog common. the reference capacitor is charged to the reference voltage. a feed- back loop is closed around the system to charge the auto-zero capacitor (c az ) to compensate for offset volt- ages in the buffer amplifier, integrator, and comparator. since the comparator is included in the loop, az accuracy is limited only by system noise. the offset referred to the input is less than 10 ? v. 3.1.2 signal integrate phase the auto-zero loop is opened, the internal short is removed, and the internal high and low inputs are connected to the external pins. the converter then inte- grates the differential voltages between v in + and v in - for a fixed time. this differential voltage can be within a wide common mode range: 1v of either supply. how- ever, if the input signal has no return with respect to the converter power supply, v in - can be tied to analog common to establish the correct common mode voltage. at the end of this phase, the polarity of the integrated signal is determined . figure 3-1: analog section of tc7116/tc7116a and tc7117/tc7117a 3.1.3 reference integrate phase the final phase is reference integrate, or de-integrate. input low is internally connected to analog common and input high is connected across the previously charged reference capacitor. circuitry within the chip ensures that the capacitor will be connected with the correct polarity to cause the integrator output to return to zero. the time required for the output to return to zero is proportional to the input signal. the digital reading displayed is: equation 3-1: 3.1.4 reference the positive reference voltage (v ref +) is referred to analog common. tc7116 tc7116a tc7117 tc7117a c ref c ref + c ref - r int v+ c az auto-zero v int 28 35 29 27 33 36 34 10 a 31 az az int az & de () 32 30 int 26 integrator v+ -3v comparator to digital section de (+) de (?) de (+) de (?) v+ az analog common v in + v in - v buff c int v ref + low temp. drift zener v ref v- + ? + ? + + ? 1000 = v in v ref
? 2002-2012 microchip technology inc. ds21457d-page 9 tc7116/a/tc7117/a 3.1.5 differential input this input can accept differential voltages anywhere within the common mode range of the input amplifier or, specifically, from 1v below the positive supply to 1v above the negative supply. in this range, the system has a cmrr of 86db, typical. however, since the inte- grator also swings with the common mode voltage, care must be exercised to ensure that the integrator output does not saturate. a worst-case condition would be a large, positive common mode voltage with a near full scale negative differential input voltage. the nega- tive input signal drives the integrator positive, when most of its swing has been used up by the positive common mode voltage. for these critical applications, the integrator swing can be reduced to less than the recommended 2v full scale swing with little loss of accuracy. the integrator output can swing within 0.3v of either supply without loss of linearity. 3.1.6 analog common this pin is included primarily to set the common mode voltage for battery operation (tc7116/tc7116a), or for any system where the input signals are floating, with respect to the power supply. the analog common pin sets a voltage approximately 2.8v more negative than the positive supply. this is selected to give a minimum end of life battery voltage of about 6v. however, analog common has some attributes of a reference voltage. when the total supply voltage is large enough to cause the zener to regulate (>7v), the analog common volt- age will have a low voltage coefficient (0.001%), low output impedance ( ? 15 ? ), and a temperature coeffi- cient of less than 20ppm/c, typically, and 50 ppm max- imum. the tc7116/tc7117 temperature coefficients are typically 80ppm/c. an external reference may be used, if necessary, as shown in figure 3-2. figure 3-2: using an external reference analog common is also used as v in - return during auto-zero and de-integrate. if v in - is different from ana- log common, a common mode voltage exists in the system and is taken care of by the excellent cmrr of the converter. however, in some applications, v in - will be set at a fixed, known voltage (power supply common for instance). in this application, analog common should be tied to the same point, thus removing the common mode voltage from the converter. the same holds true for the reference voltage; if it can be conve- niently referenced to analog common, it should be. this removes the common mode voltage from the reference system. within the ic, analog common is tied to an n-channel fet, that can sink 30ma or more of current to hold the voltage 3v below the positive supply (when a load is trying to pull the analog common line positive). how- ever, there is only 10 ? a of source current, so analog common may easily be tied to a more negative voltage, thus overriding the internal reference. 3.1.7 test the test pin serves two functions. on the tc7117/ tc7117a, it is coupled to the internally generated digi- tal supply through a 500 ? resistor. thus, it can be used as a negative supply for externally generated segment drivers, such as decimal points, or any other presenta- tion the user may want to include on the lcd. (figure 3-3 and figure 3-4 show such an application.) no more than a 1ma load should be applied. the second function is a ?lamp test.? when test is pulled high (to v+), all segments will be turned on and the display should read -1888. the test pin will sink about 10ma under these conditions. figure 3-3: simple inverter for fixed decimal point v+ v+ 1.2v ref common tc7116 tc7116a tc7117 tc7117a 6.8k v ref + 20k tc7116 tc7116a bp test 37 21 v+ v+ gnd to lcd decimal point to lcd backplane 4049
tc7116/a/tc7117/a ds21457d-page 10 ? 2002-2012 microchip technology inc. figure 3-4: exclusive ?or? gate for decimal point drive 3.2 digital section figure 3-5 and figure show the digital section for tc7116/tc7116a and tc7117/tc7117a, respectively. for the tc7116/tc7116a (figure 3-5), an internal dig- ital ground is generated from a 6v zener diode and a large p-channel source follower. this supply is made stiff to absorb the relative large capacitive currents when the backplane (bp) voltage is switched. the bp frequency is the clock frequency 4800. for 3 readings per second, this is a 60hz square wave with a nominal amplitude of 5v. the segments are driven at the same frequency and amplitude, and are in phase with bp when off, but out of phase when on. in all cases, negligible dc voltage exists across the segments. figure is the digital section of the tc7117/tc7117a. it is identical to the tc7116/tc7116a, except that the regulated supply and bp drive have been eliminated, and the segment drive is typically 8ma. the 1000?s out- put (pin 19) sinks current from two led segments, and has a 16ma drive capability. the tc7117/tc7117a are designed to drive common anode led displays. in both devices, the polarity indication is on for analog inputs. if v in - and v in + are reversed, this indication can be reversed also, if desired. figure 3-5: tc7116/tc7116a digital section tc7116 tc7116a decimal point select v+ v+ test gnd 4030 to lcd decimal point bp tc7116 tc7116a lcd phase driver thousands hundreds tens units 4 backplane 21 39 37 osc2 internal digital ground v+ v- tes t 6.2v 500 26 35 to switch drivers from comparator output clock v th = 1v 7-segment decode 7-segment decode 7-segment decode 200 40 38 typical segment output internal digital ground segment output v+ 0.5ma 2ma latch osc3 osc1 hldr ~70k logic control 1
? 2002-2012 microchip technology inc. ds21457d-page 11 tc7116/a/tc7117/a 3.2.1 system timing the clocking method used for the tc7116/tc7116a and tc7117/tc7117a is shown in figure . three clocking methods may be used: 1. an external oscillator connected to pin 40. 2. a crystal between pins 39 and 40. 3. an rc network using all three pins. the oscillator frequency is ? 4 before it clocks the decade counters. it is then further divided to form the three convert cycle phases: signal integrate (1000 counts), reference de-integrate (0 to 2000 counts), and auto-zero (1000 to 3000 counts). for signals less than full scale, auto-zero gets the unused portion of ref- erence de-integrate. this makes a complete measure cycle of 4000 (16,000 clock pulses), independent of input voltage. for 3 readings per second, an oscillator frequency of 48khz would be used. to achieve maximum rejection of 60hz pickup, the sig- nal integrate cycle should be a multiple of 60hz. oscil- lator frequencies of 240khz, 120khz, 80khz, 60khz, 48khz, 40khz, etc. should be selected. for 50hz rejec- tion, oscillator frequencies of 200khz, 100khz, 66-2/3khz, 50khz, 40khz, etc. would be suitable. note that 40khz (2.5 readings per second) will reject both 50hz and 60hz. 3.2.2 hold reading input when hldr is at a logic high, the latch will not be updated. analog-to-digital conversions will continue, but will not be updated until hldr is returned to low. to continuously update the display, connect to test (tc7116/tc7116a) or ground (tc7117/tc7117a), or disconnect. this input is cmos compatible with 70k ? typical resistance to test (tc7116/tc7116a) or ground (tc7117/tc7117a). figure 3-6: tc7117/tc7117a digital section tc7117 tc7117a 4 39 osc2 v+ digital gnd test 35 clock 40 38 osc3 osc1 hldr control logic typical segment output digital ground to segment v+ 0.5ma 8ma 37 21 500 v+ 1 latch ~70k to switch drivers from comparator output internal digital ground thousands hundreds tens units 7-segment decode 7-segment decode 7-segment decode
tc7116/a/tc7117/a ds21457d-page 12 ? 2002-2012 microchip technology inc. 4.0 component value selection 4.1 auto-zero capacitor the size of the auto-zero capacitor has some influence on system noise. for 200mv full scale, where noise is very important, a 0.47 ? f capacitor is recommended. on the 2v scale, a 0.047 ? f capacitor increases the speed of recovery from overload and is adequate for noise on this scale. 4.2 reference capacitor a 0.1 ? f capacitor is acceptable in most applications. however, where a large common mode voltage exists (i.e., the v in - pin is not at analog common), and a 200mv scale is used, a larger value is required to pre- vent rollover error. generally, 1 ? f will hold the rollover error to 0.5 count in this instance. 4.3 integrating capacitor the integrating capacitor should be selected to give the maximum voltage swing that ensures tolerance buildup will not saturate the integrator swing (approximately 0.3v from either supply). in the tc7116/tc7116a or the tc7117/tc7117a, when the analog common is used as a reference, a nominal 2v full scale integrator swing is acceptable. for the tc7117/tc7117a, with 5v supplies and analog common tied to supply ground, a 3.5v to 4v swing is nominal. for 3 read- ings per second (48khz clock), nominal values for c int are 0.22 ? 1f and 0.10 ? f, respectively. if different oscil- lator frequencies are used, these values should be changed in inverse proportion to maintain the output swing. the integrating capacitor must have low dielec- tric absorption to prevent rollover errors. polypropylene capacitors are recommended for this application. 4.4 integrating resistor both the buffer amplifier and the integrator have a class a output stage with 100 ? a of quiescent current. they can supply 20 ? a of drive current with negligible non- linearity. the integrating resistor should be large enough to remain in this very linear region over the input voltage range, but small enough that undue leak- age requirements are not placed on the pc board. for 2v full scale, 470k ? is near optimum and, similarly, 47k ? for 200mv full scale. 4.5 oscillator components for all frequency ranges, a 100k ? resistor is recom- mended; the capacitor is selected from the equation: equation 4-1: for a 48khz clock (3 readings per second), c = 100pf. 4.6 reference voltage to generate full scale output (2000 counts), the analog input requirement is v in = 2v ref . thus, for the 200mv and 2v scale, v ref should equal 100mv and 1v, respectively. in many applications, where the adc is connected to a transducer, a scale factor exists between the input voltage and the digital reading. for instance, in a measuring system, the designer might like to have a full scale reading when the voltage from the transducer is 700mv. instead of dividing the input down to 200mv, the designer should use the input voltage directly and select v ref = 350mv. suitable values for integrating resistor and capacitor would be 120kw and 0.22 ? f. this makes the system slightly quieter and also avoids a divider network on the input. the tc7117/ tc7117a, with 5v supplies, can accept input signals up to 4v. another advantage of this system is when a digital reading of zero is desired for v in ? 0. tempera- ture and weighing systems with a variable tare are examples. this offset reading can be conveniently gen- erated by connecting the voltage transducer between v in + and analog common, and the variable (or fixed) offset voltage between analog common and v in -. f 0.45 rc - - - - - - - =
? 2002-2012 microchip technology inc. ds21457d-page 13 tc7116/a/tc7117/a 5.0 tc7117/tc7117a power supplies the tc7117/tc7117a are designed to operate from 5v supplies. however, if a negative supply is not avail- able, it can be generated with a tc7660 dc-to-dc con- verter and two capacitors. figure 5-1 shows this application. in selected applications, a negative supply is not required. the conditions for using a single +5v supply are: 1. the input signal can be referenced to the center of the common mode range of the converter. 2. the signal is less than 1.5v. 3. an external reference is used. figure 5-1: negative power supply generation with tc7660 v ref + v+ tc7117 tc7117a 36 10 f v in + v in - com gnd 32 31 30 21 10 f v in v- (-5v) 5 3 8 2 4 +5v 35 tc7660 26 + + + ? led drive
tc7116/a/tc7117/a ds21457d-page 14 ? 2002-2012 microchip technology inc. 6.0 typical applications the tc7117/tc7117a sink the led display current, causing heat to build up in the ic package. if the inter- nal voltage reference is used, the changing chip tem- perature can cause the display to change reading. by reducing the led common anode voltage, the tc7117/ tc7117a package power dissipation is reduced. figure 6-1 is a curve tracer display showing the rela- tionship between output current and output voltage for typical tc7117cpl/tc7117acpl devices. since a typical led has 1.8v across it at 8ma and its common anode is connected to +5v, the tc7117/tc7117a out- put is at 3.2v (point a, figure 6-1). maximum power dissipation is 8.1ma x 3.2v x 24 segments = 622mw. however, notice that once the tc7117/tc7117a?s out- put voltage is above 2v, the led current is essentially constant as output voltage increases. reducing the output voltage by 0.7v (point b figure 6-1) results in 7.7ma of led current, only a 5% reduction. maximum power dissipation is now only 7.7ma x 2.5v x 24 = 462mw, a reduction of 26%. an output voltage reduc- tion of 1v (point c) reduces led current by 10% (7.3ma), but power dissipation by 38% (7.3ma x 2.2v x 24 = 385mw). figure 6-1: tc7117/tc7117a output vs. output voltage reduced power dissipation is very easy to obtain. figure 6-2 shows two ways: either a 5.1 ? , 1/4w resis- tor, or a 1a diode placed in series with the display (but not in series with the tc7117/tc7117a). the resistor reduces the tc7117/tc7117a?s output voltage (when all 24 segments are on) to point c of figure 6-1. when segments turn off, the output voltage will increase. the diode, however, will result in a relatively steady output voltage, around point b. in addition to limiting maximum power dissipation, the resistor reduces change in power dissipation as the display changes. the effect is caused by the fact that, as fewer segments are on, each on output drops more voltage and current. for the best-case of six segments (a ?111? display) to worst-case (a ?1888? display), the resistor circuit will change about 230mw, while a circuit without the resistor will change about 470mw. therefore, the resistor will reduce the effect of display dissipation on reference voltage drift by about 50%. the change in led brightness caused by the resistor is almost unnoticeable as more segments turn off. if display brightness remaining steady is very important to the designer, a diode may be used instead of the resistor. figure 6-2: diode or resistor limits package power dissipation c b a 6.000 7.000 8.000 9.000 10.000 2.00 2.50 3.00 3.50 4.00 output voltage (v) output current (ma) tp2 tp5 100 k tp1 24k 1k 0.1 f tp3 0.01 f + in ? 0.22 f display display 100 pf +5v 1m -5v 150k 0.47 f tc7117 tc7117a 40 tp 4 30 35 21 20 10 1 47 k 1n4001 1.5w, 1/4
? 2002-2012 microchip technology inc. ds21457d-page 15 tc7116/a/tc7117/a figure 6-3: tc7116/tc7117a using the internal reference (200 mv full scale, 3 readings per second ? rps) figure 6-4: tc7117/tc7117a internal reference (200 mv full scale, 3 rps, v in - tied to gnd for single ended inputs 100k 100pf 0.47 f 47k 0.22 f to display to backplane 0.1pf 21 1k 22k 9v set v ref = 100mv tc7116 tc7116a 0.01 f + in 1m ? 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 + ? 100k 100pf 0.47 f 47k 0.22 f to display 0.1pf 21 1k 22k set v ref = 100mv 0.01 f + in 1m ? 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 -5v +5v tc7117 tc7117a
tc7116/a/tc7117/a ds21457d-page 16 ? 2002-2012 microchip technology inc. figure 6-5: circuit for developing under range and over range signals from tc7116/tc7117a outputs figure 6-6: tc7117/tc7117a with a 1.2 external bandgap reference (v in - tied to common) 21 20 40 35 26 to logic gnd v- to logic v cc v+ cd4077 u/r o/r cd4023 or 74c10 tc7116 tc7116a o/r = over range u/r = under range 100pf 0.47 f 47k to display 0.1pf 1k v+ set v ref = 100mv 10k 10k 1.2v 0.01 f ? in 1m + 100k 0.22 f 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 tc7117 tc7117a
? 2002-2012 microchip technology inc. ds21457d-page 17 tc7116/a/tc7117/a figure 6-7: recommended component values for 2v full scale (tc7116/tc7116a and tc7117/ tc7117a) figure 6-8: tc7117/tc7117a operated from single +5v supply (an external reference must be used in this application) 100k 100pf 0.047 f 470k 0.22 f to display 0.1 f 25k 24k v+ set v ref = 1v 0.01 f + in 1m ? v- 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 tc7116 tc7116a tc7117 tc7117a 100pf 0.47 f 47k to display 0.1pf 1k v+ set v ref = 100mv 10k 10k 1.2v 0.01 f ? in 1m + 100k 0.22 f 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 tc7117 tc7117a
tc7116/a/tc7117/a ds21457d-page 18 ? 2002-2012 microchip technology inc. 7.0 packaging information 7.1 package marking information package marking data not available at this time. 7.2 taping form .557 (14.15) .537 (13.65) .398 (10.10) .390 (9.90) .031 (0.80) typ. .018 (0.45) .012 (0.30) .398 (10.10) .390 (9.90) .010 (0.25) typ. .096 (2.45) max. .557 (14.15) .537 (13.65) .083 (2.10) .075 (1.90) .041 (1.03) .026 (0.65) 7 max. .009 (0.23) .005 (0.13) 44-pin pqfp pin 1 note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging
? 2002-2012 microchip technology inc. ds21457d-page 19 tc7116/a/tc7117/a component taping orientation for 44-pin pqfp devices user direction of feed pin 1 standard reel component orientation for 713 suffix device w p package carrier width (w) pitch (p) part per full reel reel size 44-pin pqfp 24 mm 16 mm 500 13 in carrier tape, number of components per reel and reel size note: drawing does not represent total number of pins.
tc7116/a/tc7117/a ds21457d-page 20 ? 2002-2012 microchip technology inc. 7.3 package dimensions dimensions: inches (mm) 2.065 (52.45) 2.027 (51.49) .200 (5.08) .140 (3.56) .150 (3.81) .115 (2.92) .070 (1.78) .045 (1.14) .022 (0.56) .015 (0.38) .110 (2.79) .090 (2.29) .555 (14.10) .530 (13.46) .610 (15.49) .590 (14.99) .015 (0.38) .008 (0.20) .700 (17.78) .610 (15.50) .040 (1.02) .020 (0.51) 40-pin pdip (wide) pin 1 3 min. note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging dimensions: inches (mm) .015 (0.38) .008 (0.20) .620 (15.75) .590 (15.00) .700 (17.78) .620 (15.75) .540 (13.72) .510 (12.95) 2.070 (52.58) 2.030 (51.56) .210 (5.33) .170 (4.32) .020 (0.51) .016 (0.41) .110 (2.79) .090 (2.29) .065 (1.65) .045 (1.14) .200 (5.08) .125 (3.18) .098 (2.49) max. .030 (0.76) min. .060 (1.52) .020 (0.51) .150 (3.81) min. 40-pin cerdip (wide) pin 1 3 min. note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging
? 2002-2012 microchip technology inc. ds21457d-page 21 tc7116/a/tc7117/a 7.3 package dimensions (continued) dimensions: inches (mm) pin 1 component taping orientation for 44-pin plcc devices user direction of feed standard reel component orientation for 713 suffix device note: drawing does not represent total number of pins. w p package carrier width (w) pitch (p) part per full reel reel size 44-pin plcc 32 mm 24 mm 500 13 in carrier tape, number of components per reel and reel size dimensions: inches (mm) .557 (14.15) .537 (13.65) .398 (10.10) .390 (9.90) .031 (0.80) typ. .018 (0.45) .012 (0.30) .398 (10.10) .390 (9.90) .010 (0.25) typ. .096 (2.45) max. .557 (14.15) .537 (13.65) .083 (2.10) .075 (1.90) .041 (1.03) .026 (0.65) 7 max. .009 (0.23) .005 (0.13) 44-pin pqfp pin 1 note: for the most current package drawings, please see the microchip packaging specification located at http://www.microchip.com/packaging
tc7116/a/tc7117/a ds21457d-page 22 ? 2002-2012 microchip technology inc. 8.0 revision history revision d (december 2012) added a note to each package outline drawing.
? 2002-2012 microchip technology inc. advance information ds21457d-page 23 tc7116/a/tc7117/a product identification system to order or obtain information, e. g., on pricing or delivery, refer to the factory or the listed sales office . part code tc711x x x xxx 6 = lcd 7 = led a or blank* r (reversed pins) or blank (cpl pkg only) * "a" parts have an improved reference tc package code (see device selection table) }
tc7116/a/tc7117/a ds21457d-page 24 advance information ? 2002-2012 microchip technology inc. notes:
? 2002-2012 microchip technology inc. ds21457d-page 25 information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. it is your responsibility to ensure that your application meets with your specifications. microchip makes no representations or warranties of any kind whether express or implied, written or oral, statutory or otherwise, related to the information, including but not limited to its condition, quality, performance, merchantability or fitness for purpose . microchip disclaims all liability arising from this information and its use. use of microchip devices in life support and/or safety applications is entirely at the buyer?s risk, and the buyer agrees to defend, indemnify and hold harmless microchip from any and all damages, claims, suits, or expenses resulting from such use. no licenses are conveyed, implicitly or otherwise, under any microchip intellectual property rights. trademarks the microchip name and logo, the microchip logo, dspic, flashflex, k ee l oq , k ee l oq logo, mplab, pic, picmicro, picstart, pic 32 logo, rfpic, sst, sst logo, superflash and uni/o are registered trademarks of microchip technology incorporated in the u.s.a. and other countries. filterlab, hampshire, hi-tech c, linear active thermistor, mtp, seeval and the embedded control solutions company are registered trademarks of microchip technology incorporated in the u.s.a. silicon storage technology is a registered trademark of microchip technology inc. in other countries. analog-for-the-digital age, app lication maestro, bodycom, chipkit, chipkit logo, codeguard, dspicdem, dspicdem.net, dspicworks, dsspeak, ecan, economonitor, fansense, hi-tide, in-circuit serial programming, icsp, mindi, miwi, mpasm, mpf, mplab certified logo, mplib, mplink, mtouch, omniscient code generation, picc, picc-18, picdem, picdem.net, pickit, pictail, real ice, rflab, select mode, sqi, serial quad i/o, total endurance, tsharc, uniwindriver, wiperlock, zena and z-scale are trademarks of microchip technology incorporated in the u.s.a. and other countries. sqtp is a service mark of microchip technology incorporated in the u.s.a. gestic and ulpp are registered trademarks of microchip technology germany ii gmbh & co. & kg, a subsidiary of microchip technology inc., in other countries. all other trademarks mentioned herein are property of their respective companies. ? 2002-2012, microchip technology incorporated, printed in the u.s.a., all rights reserved. printed on recycled paper. isbn: 9781620768365 note the following details of the code protection feature on microchip devices: ? microchip products meet the specification cont ained in their particular microchip data sheet. ? microchip believes that its family of products is one of the most secure families of its kind on the market today, when used i n the intended manner and under normal conditions. ? there are dishonest and possibly illegal methods used to breach the code protection feature. all of these methods, to our knowledge, require using the microchip produc ts in a manner outside the operating specif ications contained in microchip?s data sheets. most likely, the person doing so is engaged in theft of intellectual property. ? microchip is willing to work with the customer who is concerned about the integrity of their code. ? neither microchip nor any other semiconduc tor manufacturer can guarantee the security of their code. code protection does not mean that we are guaranteeing the product as ?unbreakable.? code protection is constantly evolving. we at microchip are co mmitted to continuously improvin g the code protection features of our products. attempts to break microchip?s code protection feature may be a violation of the digital millennium copyright act. if such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that act. microchip received iso/ts-16949:2009 certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona; gresham, oregon and design centers in california and india. the company?s quality system processes and procedures are for its pic ? mcus and dspic ? dscs, k ee l oq ? code hopping devices, serial eeproms, microperipherals, nonvolatile memory and analog products. in addition, microchip?s quality system for the design and manufacture of development systems is iso 9001:2000 certified. quality management s ystem certified by dnv == iso/ts 16949 ==
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