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| st3917a ST3917B speech - tone/pulse dialer - led indicator july 1996 speech circuit . 2 to 4 wires conversion . present the proper dc path for the line current and the flexibility to adjust it and allow parallel phone operation . symmetrical high impedance micro- phone inputs suitable for dynamic, electret or piezoelectric transducer . asymmetrical earphone output suit- able for dynamic transducer . line loss compensation fixed inter- nally by a.g.c. . internal muting to disable speech during dialing and external muting to disable transmit amplifier during conversation mode . led indicator either for keyboard illu- mination (or on-line indication) during dialing and conversation or for tone mode indication, through mu/mfi pin dialer circuit . store up to 32 digits for last number redial buffer, lnr is inhibited if there are more than 32 digits stored . allow mixed mode dialing in pulse mode . pacifier tone provides audible indi- cation of valid key pressed in a buzz- er or/and in the earphone . timed pabx pause / 10pps pulse rate . make/break ratio : 40/60 (st3917a) and 33/67 (ST3917B) . 4 selectable options on flash dura- tion and softswitch inhibition in one of the option with 100ms flash timing . 2 selectable options : transmit mute together with led for keyboard illumi- nation or led for tone mode indication . continuous tone for each digit until key release . uses inexpensive 3.579545mhz ceramic resonator . powered from telephone line, low operating voltage for long loop ap- plication description the device consists of the speech and the dialer func- tions. it provides the dc line interface circuit that termi- nates the telephone line, analog amplifier for speech transmission and necessary signals for either dtmf and pulse dialing. when mated with a tone ringer, a complete telephone can be produced with just two ics. the dc line interface circuit develops its own line voltage across the device and it is adjustable by external resistor to suit different countrys specification. a built-in led driver can deliver excess line current to external led indicator(s) during dialing and speech mode. the led(s) can be used either for keyboard illumination purpose or for tone mode indication during softswitch and mixed mode dialing by connecting mu/mfi pin to vdd and gnd or any row respectively. the led current is limited to 17ma (typical). the speech network provides the two to four wires inter- face, electronic switching between dialing and speech and automatic gain control on transmit and receive. the dialing network buffers up to 32 digits into the lnd memory that can be later redialed with a single key input. users can store all 13 signalling keys and access several unique functions with single key entries. these functions include : pause, last number dialled (lnd), softswitch and flash. (see figure 1). the flash key simulates a hook flash to transfer calls or to activate other special features provided by the pabx or central office. the pause key stores a timed pause in the number sequence. redial is then delayed until an outside line can be accessed or some other activities occur before normal signalling resumes. a lnd key automatically redials the last number dialed. a dedicated pin mu/mfi is used to select the muting for transmit amplifier and lighted dial led for keyboard illumination or a led indicator for tone mode indication. the sel pin allows selection of any one of the four possible flash duration options. dip28 (plastic package) order codes : st3917an - ST3917Bn so28 (plastic package) order codes : st3917ad - ST3917Bd 1/16
pulse r1 r2 r3 r4 mu/mfi mic+ 1 2 3 4 5 6 7 8 9 10 28 27 26 25 24 23 22 21 20 19 mic- gtx c1 c2 c3 mode/pt osc sel hks rxout gnd v dd gdtmf 11 12 13 14 18 17 16 15 grx rxin i ref v cc ln iline led reg 3917-01.eps pin connections pin description c1, c2, c3, r4, r3, r2, r1 (keyboard inputs, pins 1, 2, 3, 25, 26, 27, 28) the device interfaces with either the standard 2 of 8 with negative common or the single contact (form a) keyboard. column 4 of the keypad is connecting to ground. a valid keypad entry is either a single row con- nected to a single column or gnd simultaneously presented to both a single row and a single col- umn. in its quiescent or standby state, during nor- mal off-hook operation, the rows are initialized at logic level 1 (v dd ) and the columns are initialized at logic level 0 (gnd). pulling any row input low enables the on chip oscillator. keyboard scanning then begins. 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd 3917-02.eps figure 1 : keyboard configuration scanning consists of rows and columns alter- nately switching high through on chip pullups. after both a row and column keys have been detected, the debounce counter is enabled and any noise (bouncing contacts, etc) is ignored for a debounce period (tkd) of 32ms. at this time, the keyboard is sampled and if both the row and column informa- tion are valid, the information is buffered into the lnd location. in the tone mode, if two or more keys in the same row or if two or more keys in the same column are depressed a single tone will be output. the tone will correspond to the common row or common column for which the two keys were pushed. this feature is for test purposes, and single tone will not be redialed. also in the tone mode, the output tone is continuous in the manual dialing as long as the key is pushed. the output tone duration follows the table 1. when redialing in the tone mode, each dtmf output is 90ms duration, and the tone sepa- ration (inter signal delay) is 90ms. table 1 : output tone duration key push time, t tone output t < 32ms 32ms < t < 90ms + tkd t > 90 ms + tkd no output, ignored by the device 90ms duration output duration = t - tkd st3917a - ST3917B 2/16 sel (input, pin 4) this is an option selectable pin for four flash duration. the four options are summarised in the table 2. for option 1, softswitch feature is inhibited. it means redialed by the lnd key in pulse mode will not repeat the softswitch and subsequent digits, only pulse digits are dialed out. table 2 : options selectable for flash duration options sel flash (ms) softswitch 1v dd 100 inhibited 2 gnd 600 enable 3 any row 300 enable 4 any col 100 enable osc (input, pin 5) only one pin is needed to connect the ceramic resonator to the oscillator circuit. the other end of the resonator is connected to gnd. the nominal resonator frequency is 3.579545mhz and any de- viation from this standard is directly reflected in the tone output frequencies. the ceramic resonator provides the time reference for all circuit functions. a ceramic resonator with tolerance of 0.25% is recommended. pulse (output, pin 6) this is an output consisting of an open drain n- channel device. during on-hook, pulse output pin is in high impedance and once off-hook, it will be pulled high by external resistor. mode/pt (input, pin 7) input (mode). mode determines the dialers de- fault operating mode. when the device is powered up or the hookswitch input is switched from on- hook (v dd ) to off-hook (gnd), the default deter- mines the signalling mode. a v dd connection defaults to tone mode operation and a gnd con- nection defaults to pulse mode operation. when dialing in the pulse mode, a softswitch fea- ture will allow a change to the tone mode whenever the * or softswitch key (tone) is depressed. sub- sequent * key inputs will cause the dtmf code for an * to be dialed. the softswitch will only switch from pulse to tone. the phone will be in pulse mode only after returning to on-hook and back to off- hook. redialed by the lnd key will repeat the softswitch unless the softswitch redial feature is inhibited. output (pt). pacifier tone output. in pulse mode, all valid key entries activate the pacifier tone. in tone mode, any non dtmf entry (flash, pause, lnd, tone) activates the pacifier tone. the paci- fier tone provides audible feedback, confirming that the key has been properly entered and accepted. it is a 500hz square wave activated upon accep- tance of valid key input after the 32ms debounce time. the square wave terminates after 75ms typically or when the valid key is no longer pres ent. the pacifier tone signal is simultaneously sent to the earphone and the buzzer. the buzzer can be removed with- out affecting this function. the resistor value set on mode/pt pin determines the level of the pacifier tone in the earphone. hks (input, pin 8) this is the hookswitch input to the device. it is a cmos input with a high pull up internal resistance and must be switched high or open for on-hook operation and low for off-hook operation. a transi- tion on this input causes the on-chip logic to initial- ize, terminating any operation in progress at the time. the signalling mode defaults to the mode selected at mode/pt pin. figures 2, 3 and 4, 5 illustrate the timing for this pin. gnd (pin 9) gnd is the negative line terminal of the device. this is the voltage reference for all specifications. rxout, grx, rxin (pins 10, 11 and 12) the receive amplifier has one input rxin and a non inverting output rxout. amplification from rxin to rxout is typically 31db and it can be adjusted between 21db and 41db to suit the sensitivity of the earphone used. the amplification is propor- tional to the external resistor connected bet ween grx and rxout. for the hearing impaired, a specific application to offer 17db additional gain at 3khz is permitted. i ref (pin 13) an external resistor of 3.6k w connected between iref and gnd will set the internal current level. any change of this resistor value will influence the microphone gain, dtmf gain, earphone gain and sidetone level. v cc (pin 14) v cc is the positive supply of the speech network. it can be stabilized by a decoupling capacitor be- tween v cc and gnd. the v cc supply voltage may also be used to supply external peripheral circuits. pin description (continued) st3917a - ST3917B 3/16 led (output, pin 15) when the mu/mfi pin is connected to either v dd or gnd, the led connected to the led pin, which functions as a keyboard illumination or off-hook indicator, will light up when the telephone is off- hook. when the mu/mfi pin is connec ted to any row pins, the led connected to led pin functions as a tone mode indicator. from minimum operating line current up to 20ma, i ln -i cc is sourced into the led with a maximum current limit of 18ma. for line current more than 20ma, this sourced current is limited at 18ma (typical). iline (pin 16) a recommended external resistor of 20 w is con- nected between iline and gnd. changing this resistor value will influence the microphone gain, dtmf gain, sidetone, maximum output swing on ln and the dc characteristics, especially in the low voltage region. ln (pin 17) ln is the positive line terminal of the device. reg (pin 18) the internal voltage regulator has to be decoupled by a capacitor from reg to gnd. the dc charac- teristics can be changed with an external resistor connected between ln and reg or between reg and iline. gtx, mic-, mic+ (pins 19, 20, 21) the device has a symmetrical microphone inputs. the amplification from microphone inputs to ln is 51db at 15ma line current and it can be adjusted between 43 and 51db. the amplification is propor- tional to the external resistor connec ted between gtx and reg. gdtmf (pin 22) when the dtmf input is enabled, the microphone inputs and the receive amplifier input will be muted and the dialing tone will be sent on the line. the voltage amplification from gdtmf to ln is 40db. final output level on the ln can be adjusted via the external resistor connected between gdtmf and gnd through a decoupling capacitor. a confidence tone is sent to the earphone during tone dialing. the attenuation of the confidence tone from ln to rxout is -32db typically. the level of the confi- dence tone in the earphone can be increased by adjusting the resistor connected between gdtmf and grx pins, the possible range is 20db. v dd (pin 23) v dd is the positive supply for the dialing circuit and it must meet the maximum and minimum voltage requirements. mu/mfi (input, pin 24) a logic low input to this pin will disable the transmit amplifier of the speech circuit. mute efficiency is greater than 60db. an open circuit to this pin will enable the transmit amplifier. in this case, led is used for keypad lighting. a connection to any row will disable the transmit mute function and the led connected to the led pin is used for tone mode indication. table 3 : logic of mu/mfi pin indicator mu/mfi pin transmit muting led at pin 15 open active lighted dial indicator gnd muted lighted dial indicator any row not available tone mode indicator pin description (continued) st3917a - ST3917B 4/16 9 10 11 12 13 14 16 18 19 20 21 22 gm mic+ mic- k i ref gm k i ref gdtmf v1 ri2 gm k i ref gm k i ref i1 ri1 grx rxout rgrx + c9 iline/iled control iref i ref v cc dtmf generator logic + dac mute oscillator keyboard interface pulse interface ram redial 4 6 7 8 15 17 23 mode hks sel pulse ln led v dd 24 5 osc mu/mfi ci ri 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd 3.58mhz ceramic rmf cmf c14 r14 c10 st3917a/b c8 + d12 r15 la lb r20 rgtx r21 c20 c11 gtx iline reg rxin gnd r24 r25 ln secret 3917-03.eps block diagram st3917a - ST3917B 5/16 absolute maximum ratings symbol parameter value unit v ln positive line voltage continuous 12 v i ln line current 140 ma v dd logic voltage 7 v v i maximum voltage on pulse, sel, hks, mode, ri, ci, mu/mfi and osc pins gnd(-0.3) v dd (+0.3) v t oper operating temperature -25, +70 c t stg storage temperature -40, +125 c p tot total power dissipation 700 mw 3917-01.tbl electrical characteristics (i ln = 10ma to 120ma, f = 1khz, t amb = 25c, v dd = 3v ; unless otherwise specified) symbol parameter test conditions min. typ. max. unit v ln line voltage (see figure 6) i ln = 4ma i ln = 15ma i ln = 120ma i ln = 15ma, ra = 68k w i ln = 15ma, rb = 39k w 3.15 2.60 3.60 3.50 3.20 4.10 2.70 3.85 7.00 3.70 4.70 v v v v v v dd logic voltage (see figure 6) tone mode pulse mode 2.50 2.00 6.00 6.00 v v i dd supply current into v dd (see figure 6) v dd = 3v tone mode pulse mode 600 300 900 600 m a m a i cc supply current into v cc (see figure 6) i ln = 15ma 1.3 ma i led supply current to led (see figure 6) i ln = 10 - 20ma i ln = 20 - 120ma 10 i ln - i cc 24 ma ma v mr memory retention voltage (see figure 7) v dd = 3v 1.5 v i mr memory retention current (see figure 7) v dd = 3v 1 m a is off-hook standby current (see figure 6) v dd = 3v 100 250 m a i pl pulse output sink current (see figure 6) v out = 0.5v 1 3 ma i po pacifier tone sink/source current (see figure 6) v out = 0.5v(sink) v out = 2.5v(source) 1.00 0.60 3.00 1.00 ma ma v il hks, mode, keyboard inputs low 0.3xv dd v v ih hks, mode, keyboard inputs high 0.7xv dd v g tx transmit gain (see figure 9) v mic = 2mv rms i ln = 15ma, r gtx = 68k w i ln = 60ma, r gtx = 68k w 49.5 43 51 45 52.5 47 db db a gtx transmit gain variation (see figure 9) i ln = 15ma, v mic = 2mv rms r gtx = 43k w r gtx = 27k w -8 -4 -8 0db db db d tx transmit distortion (see figure 9) i ln = 15ma, v ln = 1v rms 2% n tx transmit noise (see figure 9) i ln = 15ma, v mic = 0v -72 dbmp z mic microphone input impedance (see figure 8) 50 64 80 k w g dtmf dtmf gain (see figure 10) r dtmf = 2.25k w , c dtmf = 22nf 37 39 41 db c dtmf dtmf confidence tone attenuation (see figure 10) -34 -31.5 -29 db v dtmf dtmf level on the line (see figure 10) high frequency group low frequency group r dtmf = 2.25k w , c dtmf = 22nf -8 -10 -6 -8 -4 -6 dbm dbm p ei pre-emphasis (see figure 10) 1 2 3 db dis dtmf output distortion (see figure 10) 5 8 % 3917-02.tbl st3917a - ST3917B 6/16 symbol parameter test conditions min. typ. max. unit z dtmf dtmf attenuation pin impedance 25 32 39 k w g rx receive gain (see figure 11) v inp = 4mv rms , r e = 300 w , r grx =100k w i ln = 15ma i ln = 60ma 29.5 23.0 31.0 25.0 32.5 27.0 db db a grx receive gain variation (see figure 11) v inp = 4mv rms , r e = 300 w , i ln = 15ma r grx = 10k w r grx = 300k w -20 -20 +10 10 db db db d rx receive distortion (see figure 11) i ln = 15ma, r grx =100k w r e = 150 w , v ear = 0.25v rms r e = 300 w , v ear = 0.45v rms r e = 450 w , v ear = 0.55v rms 2 2 2 % % % n rx receive noise (see figure 11) i ln = 15ma, r e = 300 w r grx = 100k w , v inp = 0v 200 m v z out receive output impedance (see figure 11) i ln = 15ma 35 w v pt pacifier tone level on earphone (see figure 11) i ln = 15ma r p = r p = 430k w 60 600 mv rms mv rms tkd fks kru krd keyboard interface keypad debounce time keypad scan frequency keypad pullup resistance keypad pulldown resistance see figures 4 and 5 32 250 100 500 ms hz k w w tris tr tpsd tisd tdur tone mode tone output rise time tone signalling rate presignal delay intersignal delay tone output duration see figures 2 and 3 40 5.55 90 90 5ms 1/sec ms ms ms tpt fpt pr tb tm idp pdp pulse mode pacifier tone duration pacifier tone frequency pulse rate break time : st3917a ST3917B make time : st3917a ST3917B interdigital pause predigital pause : st3917a ST3917B see figures 4 and 5 75 500 10 60 67 40 33 820 50 43 ms hz pps ms ms ms ms ms ms ms option selectable symbol parameter option 1 sel = v dd option 2 sel = gnd option 3 sel = row option 4 sel = col unit t flash timed hook flash (see figures 2 and3) 100 600 300 100 ms notes : 1. all inputs unloaded. quiescent mode (oscillator off). 2. pulse output sink current for v out = 0.5v at v dd = 3v. 3. pacifier tone sink current for v out = 0.5v, source current for v out = 2.5v at v dd = 3v. 4. memory retention voltage is the point where memory is guaranteed but circuit operat ion is not. proper memory retention is guaranteed if either the minimum i mr is provided or the minimum v mr . the design does not have to provide both the minimum current and voltage. 5. option 1 is with softswitch inhibition. 3917-02.tbl electrical characteristics (continued) (i ln = 10ma to 120ma, f = 1khz, t amb = 25c, v dd = 3v ; unless otherwise specified) st3917a - ST3917B 7/16 device operation during on-hook all keypad inputs are high imped- ance internally and it requires very low current for memory retention. at anytime, row inputs are initial- ized at logic level 1 and column inputs are initialized at logic level 0 at off-hook. the circuit verifies that a valid key has been entered by alternately scan- ning the row and column inputs. if the input is still valid following 32ms of debounce, the digit is stored into memory, and dialing begins after a pre-signal delay of approximately 40ms measured from the initial key closure. output tone duration is shown in table 1. the device allows manual dialing of an indefinite number of digits, but if more than 32 digits are dialed, lnd will be inhibited. table 4 : dtmf output frequencies (hz) key input std frequency output frequency % in deviation row 1 row 2 row 3 row 4 column 1 column 2 column 3 697 770 852 941 1209 1336 1477 699.1 766.2 847.4 948 1215.9 1331.7 1471.9 +0.31 -0.49 -0.54 +0.74 +0.57 -0.32 -0.35 normal dialing d d d ... normal dialing is straight forward, all keyboard entries will be stored in the buffer and signalled in succession. hook flash d flash d ... hook flash may be entered into the dialed sequence at any point by keying in the function key, flash. when a flash key is pressed, no further key inputs will be accepted until the hookflash function has been dialed. the key input following a flash will be stored as the initial digit of the new number (overwriting the number dialed before the flash) unless it is another flash. flash key pressed immediately after hook- switch or lnd will not clear the lnd buffer unless digits are entered following the flash key. flash lnd not cleared lnd flash lnd not cleared lnd flash d1 d2 lnd buffer will contain d1, d2 last number dialed off-hook lnd last number redialing is accomplished by entering the lnd key at off-hook or after the flash key, the subsequent lnd keys pressed will be ignored. sequence digit emitted off-hook, d1, d2, on-hook d1, d2 off-hook, lnd, lnd, on-hook d1, d2 off-hook, d3, d4, lnd, on-hook d3, d4 off-hook, lnd, on-hook d3, d4 last number dialed inhibition last number redialing by lnd key is inhibited if there are more than 32 digits stored. last number dialed cascading digits dial after the lnd will cascade into the lnd buffer for the next redialing. in cascade operation, the keyboard is inhibited upon pressing the lnd key, the lnd output must be completed before acceptance of any key entry. sequence digit emitted off-hook, d1, d2, on-hook d1, d2 off-hook, lnd, d3, d4, on-hook d1, d2, d3, d4 off-hook, lnd, on-hook d1, d2, d3, d4 pause off-hook d pause d ... a pause may be entered into the dialed sequence at any point by keying in the special function key, pause. pause inserts a 3.1 seconds (tone mode) or 3.4 seconds (pulse mode) delay into the dialing sequence. the total delay, including predigit and post digit pauses as shown in table 5. table 5 : special function delays function first / auto delay (second) pulse tone soft- switch first auto 0.2 1 pause first auto 2.6 3.4 3.0 3.1 each delay shown in table 5 represents the time required from the time the special function key is depressed until a new digit is dialed. the time is considered "first" key if all previous inputs have been completely dialed. the time is considered "auto" if in redial, or if previous digits dialing is still in progress. st3917a - ST3917B 8/16 led indicator / tone mode indication when the mu/mfi (pin 24) is connected to any row of the keypad input, the led connected to pin 15 (led) becomes a tone mode indicator. the led indicator is used in the following conditions : - at tone mode, led will light up at off-hook. the led will turn off only when the telephone goes on-hook. example : tone mode off-hook (led turns on) keyboard scan dtmf output (pin 17) pulse output led keyboard input on off on tflash 3 3 keyboard scan 1 flash * 3 enter enter enter enter dial sequence 1 * flash 3 3 : debounce time 3 3917-06.eps figure 4 : pulse mode timing with lighted dial led (pin 24 to v dd or gnd) lnd keyboard scan dtmf output (pin 17) pulse output led keyboard input on off on tflash 3 3 3 keyboard scan 1 flash * enter enter enter enter dial sequence 1 * flash 3 : debounce time lnd off 3917-07.eps figure 5 : pulse mode timing with tone indicator using "*" or "tone" key keyboard scan dtmf output (pin 17) pulse output led keyboard input on off on tflash 3 3 3 keyboard scan 1 flash * 3 enter enter enter enter dial sequence 1 * flash 3 3 : debounce time 3917-05.eps figure 3 : tone mode timing with tone indicator (pin 24 to any row) st3917a - ST3917B 10/16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd secret col row 3.58mhz ma ipl v dd 100k w pulse tone sw2 sw1 rgrx 100pf 10f re 3.9k w + 100f + 620 w i cc 100nf rdtmf cdtmf 470nf 1f 1f rgtx 100pf 4.7f + ra led i led rb 130k w 3.9k w 390 w 20 w 390 w 600 w 100f + i ln i dd v ln 3917-08.eps figure 6 : te st 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd secret col row 3.58mhz v mr 100k w pulse tone sw2 sw1 rgrx 100pf 10f re 3.9k w + 100f + 620 w 100nf rdtmf cdtmf 470nf 1f 1f rgtx 100pf 4.7f + led 130k w 3.9k w 390 w 20 w 390 w i mr 470k w 3917-09.eps figure 7 : te st st3917a - ST3917B 11/16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd secret col row 3.58mhz 100k w pulse tone sw2 sw1 rgrx 100pf 10f re 3.9k w + 100f + 620 w 100nf rdtmf cdtmf 470nf rgtx 100pf 4.7f + led 130k w 3.9k w 390 w 20 w 390 w 470k w 1.2v imic zmic = 1.2 imic 3917-10.eps figure 8 : te st 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd secret col row 3.58mhz v dd 100k w pulse tone sw2 sw1 rgrx 100pf 10f re 3.9k w + 100f + 620 w 100nf rdtmf cdtmf 470nf 1f 1f rgtx 100pf 4.7f + led 130k w 3.9k w 390 w 20 w 390 w 600 w 100f + i ln v ln 470k w vmic gtx = 20 log v ln vmic 3917-11.eps figure 9 : te st st3917a - ST3917B 12/16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd secret col row 3.58mhz v dd 100k w pulse tone sw2 sw1 rgrx 100pf 10f re 3.9k w + 100f + 620 w 100nf rdtmf cdtmf 470nf 1f 1f rgtx 100pf 4.7f + led v ear 130k w 3.9k w 390 w 20 w 390 w 600 w 100f + i ln v ln 470k w gdtmf = 20 log v ln v mf v mf cdtmf = 20 log vear v ln 3917-12.eps figure 10 : te st 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd secret col row 3.58mhz v dd 100k w pulse tone sw2 sw1 rgrx 100pf 10f re 3.9k w + 100f + 620 w 100nf rdtmf cdtmf 470nf 1f 1f rgtx 100pf 4.7f + led v ear 130k w 3.9k w 390 w 20 w 390 w 100f + i ln v ln 470k w grx = 20 log v ear v inp v inp 3917-13.eps figure 11 : te st st3917a - ST3917B 13/16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 c1 c2 c3 sel osc pulse mode/pt hks gnd rxout grx rxin i ref v cc r1 r2 r3 r4 mu/mfi v dd gdtmf mic+ mic- gtx reg ln iline led st3917a/b 1 2 3 4 5 6 7 8 9 * 0 # flash tone/pulse pause lnd 3.58mhz 100k w pulse dtmf hks2 100k w 4.7f 3.6k w + 100f + 100nf 3.3k w 10nf 470nf 47k w 10f + led zsidetone 20 w microphone 3.9k w 4.7nf 620 w bat42 470f + 5.6v earphone ceramic options 2sa1013 100k w 3.3k w bf393 5.6k w 150k w 10v 10m w 1 2 3 4 5 6 7 8 l3240 buzzer 24k w + 10f 100nf 2.2k w 1f hks1 10 w a b secret 3917-14.eps typical application st3917a - ST3917B 14/16 pm-dip28.eps package mechanical data 28 pins - plastic package dimensions millimeters inches min. typ. max. min. typ. max. a1 0.63 0.025 b 0.45 0.018 b1 0.23 0.31 0.009 0.012 b2 1.27 0.050 d 37.4 1.470 e 15.2 16.68 0.598 0.657 e 2.54 0.100 e3 33.02 1.300 f 14.1 0.555 i 4.445 0.175 l 3.3 0.130 dip28.tbl st3917a - ST3917B 15/16 pm-so28.eps package mechanical data 28 pins - plastic package dimensions millimeters inches min. typ. max. min. typ. max. a 2.65 0.104 a1 0.1 0.3 0.004 0.012 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.013 c 0.5 0.020 c1 45 o (typ.) d 17.7 18.1 0.697 0.713 e 10 10.65 0.394 0.419 e 1.27 0.050 e3 16.51 0.65 f 7.4 7.6 0.291 0.299 l 0.4 1.27 0.016 0.050 s8 o (max.) so28.tbl information furnished is believed to be accurate and reliable. however, sgs-thomson microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. no licence is granted by implication or otherwise under any patent or patent rights of sgs-thomson microelectroni cs. specifications mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information previously supplied. sgs-thomson microelectronics products are not authorized for use as critical components in lif e support devices or systems without express written approval of sgs-thomson microelectronics. ? 1996 sgs-thomson microelectronics - all rights reserved purchase of i 2 c components of sgs-thomson microelectronics, conveys a license under the philips i 2 c patent. rights to use these components in a i 2 c system, is granted provided that the system conforms to the i 2 c standard specifications as defined by philips. sgs-thomson microelectronics group of companies australia - brazil - canada - china - france - germany - hong kong - it aly - japan - korea - malaysia - malta - morocco the netherlands - singapore - spain - sweden - switzerland - taiwan - thailand - united kingdom - u.s.a. st3917a - ST3917B 16/16 |
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