this document is for maintenance purposes only and is not recommended for new designs 4 .com u datasheet
MV5087 1 ds3125-2.0 june 1993 MV5087 dtmf generator the MV5087 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 either a standard 2-of-8 or a single contact (form a) keyboard. 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. tone out single tone inhibit row 1 row 2 row 3 row 4 mute column 4 +v dd xmitr column 1 column 2 column3 v ss osc in osc out dp16 mp16 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 figure 1: pin connections - top view features n pin-for-pin replacement for mk5087 n low standby power n minimum external parts count n 3.5v to 10v operatlon n 2-of-8 keyboard or calculator-type single contact (form a) keyboard input n on-chip regulation of output tone n mute and transmitter drivers on-chip n high accuracy tones provided by 3.58mhz crystal oscillator n pin-selectable inhibit of single tone generation applications dtmf signalling for n telephone sets n mobile radio n remote control n point-of-sale and banking terminals n process control + - v ref v dd v dd tone out xmitr mute out d/a converter d/a converter sine wave counter sine wave counter transmit/mute logic v ss 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 dd single tone inhibit MV5087 figure 2: functional block diagram 4 .com u datasheet
MV5087 2 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 = 3.5v to 10v characteristics operating supply voltage standby supply current operating supply current single tone input high voltage inhibit input low voltage input resistance row 1-4 input high voltage input low voltage column 1-4 input high voltage input low voltage xmitr source current leakage current mute sink current source current symbol v dd i dds i dd v ih v il r in v ih v il v ih v il i oh i oz i ol i oh min. 3.5 0.7v dd 0 0.9v dd 0.7v dd -15 -50 0.5 1.0 -0.5 -1.0 typ. 0.2 0.5 1.0 5.0 60 -25 -100 0.1 max. 10 100 200 2.0 10.0 v dd 0.3v dd 0.3v dd 0.1v dd 10 units v ua ua ma ma v v k w v v v v ma ma ua ma ma ma ma ref. to v ss v dd = 3.5v no key depressed v dd = 10v all outputs unloaded v dd = 3.5v one key depressed v dd = 10v all outputs unloaded v dd = 3.5v, v oh = 2.5v v dd = 10v, v oh = 8v v dd = 10v, v oh = 0v v dd = 3.5v, v ol = 0.5v v dd = 10v, v ol = 0.5v v dd = 3.5v, v oh = 3.0v v dd = 10v, v oh = 9.5v no keyboard entry keyboard entry no keyboard entry keyboard entry outputs inputs supply ac electrical characteristics test conditions (unless othenwise stated): t amb = +25 c, v dd = 3.5v to 10v symbol v or v oc r l t r min. 320 400 700 300 1 typ. 400 500 3 max. 500 630 -20 3 5 single tone r l = 1k w v dd = 3.5v v dd = 10v total out-of-band power relative to sum of row and column fundamental power units mv rms mv rms w w db db ms characteristics tone out row tone output voltage column tone output voltage external load impedance output distortion pre emphasis, high band tone output rise time 4 .com u datasheet
MV5087 3 pin functions pin name description v dd positive power supply 2 xmitr emitter output of a bipolar transistor whose collector is connected to v dd . with no keyboard input this output remains at v dd and a keyboard input changes the output to a high impedance state. the state of single tone inhibit input has no effect on xmitr output. 3,4,5,9 column 1-4 these inputs are held at v ss by resistors rc and sense a valid logic level (approx 1 / 2 v dd ) when tied to a row input. v 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 mute this cmos output switches to v ss with no keyboard input and to v dd with a keyboard input. this output is unaffected by the state of single tone inhibit . 11,12,13,14 row 1-4 these inputs are held at v dd by resistors r r and sense a valid logic level (approx 1 / 2 v dd ) when tied to a column input. 15 single tone this input has a pull-up resistor to v dd and when left unconnected or tied to v dd , inhibit single or dual tones may be generated. when vss is applied dual tones only are generated and no input combinations will cause generation of a single tone. 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, and regulates the output level of, the row and column tones. row and column inputs these inputs are compatible with the standard 2-of-8 keyboard, single contact (form a) keyboard and electronic input. figures 3 and 4 show these input configurations, and fig. 5 shows the internal structure of these inputs. when operating with a keyboard, dual tones are generated when any single button is pushed. single tones are generated when more than one button is pushed in any row or column. no tones are generated when diagonallypositioned buttons are simultaneously pressed. an electronic input to a single column generates that single column tone. inputs to multiple columns generates no tone. an electronic input to a single row generates no tone and a single row tone may be generated only by activating 2 columns and the desired row. class a keyboard col row row col 2 of 8 dtmf keyboard column row v dd v dd v ss v ss static protection static protection row input sensing circuit column input sensing circuit row input column input v dd v ss r c r r figure 4: electronic input figure 5: row and column inputs figure 3: keyboard configuration 4 .com u datasheet
MV5087 4 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.6), resulting in a ?taircase?approximation 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. v out v out t t a) b) figure 6: typical sinewave output (a) row tones (b) column tones col v 2 + v 2 row 4 .com u datasheet
MV5087 5 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 xmitr 3.58 mhz xtal single tone inhibit v dd v ss mute row 4 row 3 row 2 row 1 col 4 col 3 col 2 col 1 MV5087 figure 7: connection diagram 4 .com u datasheet
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