this document is for maintenance purposes only and is not recommended for new designs
MV5089 1 ds3126-2.0 june 1993 MV5089 dtmf generator the MV5089 is fabricated using iso-cmos high density technology and offers low power and wide voltage operation. an inexpensive 3.58mhz tv crystal completes the reference oscillator. from this frequency are derived 8 different sinusoidal frequencies which, when appropriately mixed, provide dual-tone multi-frequency (dtmf) tones. inputs are compatible with a standard 2-of-8 active-low keyboard and the keyboard entries determine the correct division of the reference frequency by the row and column counters. d-to-a conversion, using r-2r ladder networks, results in a staircase approximation of a sinewave with low total distortion. frequency and amplitude stability over operating voltage and temperature range are maintained within industry specifications. figure 1: pin connections - top view figure 2: functional block diagram applications dtmf signalling for n telephone sets n mobile radio n remote control n point-of-sale and banking terminals n process control features n pin-for-pin replacement for mk5089 n low standby power n minimum external parts count n 2.75v to 10v operatlon n 2-of-8 keyboard input n high accuracy tones provided by 3.58mhz crystal oscillator n pin-selectable inhibit of single tone generation tone out single tone inhibit row 1 row 2 row 3 row 4 any key down column 4 v dd tone disable column 1 column 2 column 3 v ss osc in osc out dp16 mp16 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 + - v dd v dd tone out tone disable any key down d/a converter d/a converter sine wave counter sine wave counter v dd r c r c r c r c 1234 { column inputs v ss osc in osc out keyboard logic ? 4 column counter row counter v dd { keyboard logic 1234 row inputs r r r r r r r r v dd v ss single tone inhibit v ss keyboard logic v dd 1 / 2
MV5089 2 output frequency table 1 shows the output frequency deviation from the standard dtmf frequencies when a 3.58mhz crystal is used as the reference. the row and column output waveforms are digitally synthesised using r-2r d-to-a converters (see fig.3), resulting in staircase approximations to a sinewave. an opamp mixes these tones to produce a dual-tone waveform. single tone distortion is typically better than 7% and all distortion components of the mixed dual-tone should be 30db relative to the strongest fundamental (column tone). distortion measurements thd for the single tone is defined by: tone output frequency using 3.5795545 mhz crystal standard dtmf (hz) f 1 697 f 2 770 f 3 852 f 4 941 f 5 1209 f 6 1336 f 7 1477 f 8 1633 % deviation from standard +0.62 +0.19 +0.61 -0.63 +0.57 -0.32 -0.35 +0.73 701.3 771.4 857.2 935.1 1215.9 1331.7 1471.9 1645.0 column row high group low group table 1: output frequency deviation 100 ( v 2 + v 2 + v 2 + ---- v 2 ) % 2f 3f 4f nf v fundamental 100 ( v 2 + v 2 + v 2 + v 2 + v 2 --- v 2 + v 2 ) 2r 3r nr where v2f --- vnf are the fourier components of the waveform. thd for the dual tone is defined by: 2c 3c nc imd where v row is the row fundamental amplitude v col is the column fundamental amplitude v 2r ? nr are the fourier component amplitudes of the row frequencies v 2c ? nc are the fourier component amplitudes of the column frequencies v imd is the sum of all intermodulation components. figure 3: typical sinewave output (a) row tones (b) column tones col v 2 + v 2 row v out v out t t a) b)
MV5089 3 pin functions pin name description 1v dd positive power supply 2 tone this input has an internal pull-up resistor to v d d. when connected to v ss no disable tones are generated by ant key depression allowing the keyboard to be used for purposes other than dtmf signalling. 3,4,5,9 column 1-4 these cmos inputs are held at v ss by an internal pull-up resistor and are activated by the application of v ss . 6v ss negative power supply (ov) 7,8 osc in, on-chip inverter completes the oscillator when a 3,579545 mhz crystal is osc out connected to these pins. osc in is the inverter input and osc out is the output. 10 any key down this is an nmos transistor output which switches to vss while any key is depressed. otherwise this output is high impedance. switching is independent of tone disable and single tone inhibit. 11,12,13,14 row 1-4 as column 1-4 inputs. 15 single tone this input has a pull-up resistor to v ss . when left unconnected or tied to v ss , inhibit dual tones may be generated, but keyboard input combinations resulting in single tone generation are inhibited. when vdd is applied single or dual tones may be generated. 16 tone out emitter output of a bipolar npn transistor whose collector is tied to v dd . input to this transistor is from an op-amp which mixes the row and column tones. figure 6: row and column inputs figure 4: 2 of 8 dtmf keyboard row and column inputs these inputs are compatible with the standard 2-of-8 keyboard or with an electronic input. figures 4 and 5 show these input configurations and fig.6 shows the internal chip structure of these inputs. when operating with a keyboard, dual tones are generated when any single button is pushed. with single tone inhibit at v dd , connection of v ss to a single column causes the generation of that column tone. connection of v ss to more than one column will result in no column tones being generated. connection of v ss to rows only generates no tone - a column must be connected to v ss . a single row tone only may be generated by connecting 2 columns, and the desired row, to v ss . output tone level the output tone level of the MV5089 is proportional to the applied dc supply voltage. a regulated supply will normally be used which may be designed to provide stability over the temperature range. row col v ss figure 5: electronic input static protection static protection row input sensing circuit column input sensing circuit row input column input v dd v dd r c r r column row v dd v dd v ss v ss
MV5089 4 characteristics tone out output level, row pre emphasis, high band output distortion (dual tone) tone output rise time absolute maximum ratings min. max. min. max. v dd - v ss -0.3v 10.5v power dissipation 850 mw voltage on any pin v ss - 0.3v v dd + 0 3v derate 16 mw/ c above 75 c current on any pin 10 ma (all leads soldered to pcb) operating temperature -40 c +85 c storage temperature -65 c +150 c dc electrical characteristics test conditions (unless othenwise stated): t amb = +25 c, v dd = 3v to 10v characteristics operating supply voltage standby supply current operating supply current single tone input high voltage inhibit input low voltage tone disable input resistance row 1-4 input high voltage column 1-4 input low voltage any key sink current down leakage current symbol v dd i dds i dd v ih v il r in v ih v il i ol i oz min. 2.75 0.7v dd 0 0.7v dd 0 0.5 1.0 typ. 0.2 0.5 1.0 5.0 60 1 max. 10 100 200 2.0 10.0 v dd 0.3v dd v dd 0.3v dd units v ua ua ma ma v v k w v v ma ma ua ref. to v ss v dd = 3v no key depressed v dd = 10v all outputs unloaded v dd = 3v one key depressed v dd = 10v all outputs unloaded v dd = 3v, v ol = 0.5v v dd = 10v, v ol = 0.5v v dd = 3v, supply inputs outputs ac electrical characteristics test conditions (unless othenwise stated): t amb = +25 c, v dd = 3v to 10v min. -10 2.4 typ. -8 2.7 3 max. -7 3.0 -20 5 v dd = 3v. single tone. r l = 100k w total out-of-band power relative to sum of row and column fundamental power time for waveform to reach 90% of magnitude of either frequency from initial key stroke units dbm db db ms symbol v out t r
MV5089 5 figure 7: connection diagram 123a 456b 789c * 0#d 3 4 5 9 14 13 12 11 115 7 8 2 16 610 v ss r l tone output tone disable 3.58 mhz xtal single tone inhibit v dd v ss any key down row 4 row 3 row 2 row 1 col 4 col 3 col 2 col 1 MV5089 v ss
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