4-1 semiconductor description the cd22204 complete dual tone multiple frequency (dtmf) receiver detects a selectable group of 12 or 16 standard digits. no front-end pre-?ltering is needed. the only externally required com- ponents are an inexpensive 3.579545mhz tv colorburst crystal (for frequency reference) and a bias resistor. extremely high sys- tem density is possible through the use of the alternate time base (atb) output of a crystal connected cd22204 receiver to drive the time bases of up to 10 additional receivers. this is a monolithic integrated circuit fabricated with low power, complementary sym- metry cmos processing. it only requires a single power supply. the cd22204 employs state-of-the-art switched-capacitor ?lter technology, resulting in approximately 40 poles of ?ltering and dig- ital circuitry on the same cmos chip. the analog input is prepro- cessed by 60hz reject and bandsplitting ?lters and then zero-cross detected to provide agc. eight bandpass ?lters detect the individ- ual tones. digital processing is used to measure the tone and pause durations and provides the correctly coded and timed digital outputs. the outputs interface directly to standard cmos circuitry and are three-state enabled to facilitate bus oriented architectures. features ? no front end band splitting filters required ? single low tolerance 5v supply ? three-state outputs for microprocessor based systems ? detects all 16 standard dtmf digits ? uses inexpensive 3.579545mhz crystal ? excellent speech immunity ? output in 4-bit hexadecimal code ? excellent latch-up immunity ordering information part number temp. range ( o c) package pkg. no. cd22204e 0 to 70 14 ld pdip e14.3 CD22204M 0 to 70 24 ld plastic soic m24.3 january 1997 pinouts cd22204 (pdip) top view cd22204 (soic) top view d2 d1 en v dd nc xen analog d4 d8 dv atb xin xout v ss 1 2 3 4 5 6 7 14 13 12 11 10 9 8 in 1 2 3 4 5 6 7 8 9 10 11 12 d2 d1 en nc nc v dd nc nc nc nc xen ain 16 17 18 19 20 21 22 23 24 15 14 13 d4 nc nc dv nc nc nc xout v ss d8 atb xin functional diagram high b/p filters low b/p filters voltage reg./ref. clock generator chip clocks atb xen 11 6 10 9 48 detectors and signal- processing circuits 5 12 2 1 14 13 3 dv d1 d4 d8 en xin xout d2 v ss v dd preprocessor/ bandsplit filter analog in 7 nc note: pin numbers are for pdip. cd22204 5v low power subscriber dtmf receiver caution: these devices are sensitive to electrostatic discharge. users should follow proper ic handling procedures. copyright ? harris corporation 1997 file number 1696.3
4-2 cd22204 absolute maximum ratings (note 1) thermal information dc supply voltage (v dd ) (referenced to v ss terminal) . . . . . . . 7v power dissipation t a = 25 o c (derate above t a = 25 o c at 6.25mw/ o c. . . . . . . . 65mw input voltage range all inputs except analog in . . . . . . . . . . . . . . . (v dd 0.5v) to -0.5v analog in voltage range . . . . . . . . . . . . . (v dd 0.5v) to (v dd -10v) dc current into any input or output . . . . . . . . . . . . . . . . . . . . . . 20ma maximum junction temperature . . . . . . . . . . . . . . . . . . . . . . . 175 o c maximum junction temperature (plastic) . . . . . . . . . . . . . . . . 150 o c maximum storage temperature range . . . . . . . . . . -65 o c to 150 o c maximum lead temperature (soldering 10s) . . . . . . . . . . . . . 300 o c operating conditions temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 o c to 70 o c caution: stresses above those listed in absolute maximum ratings may cause permanent damage to the device. this is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this speci?cation is not implied. electrical speci?cations 0 o c t a 70 o c, v dd = 5v 10% parameter test conditions min typ max units frequency detect bandwidth (1.5 + 2hz) 2.3 3.5 % of f o amplitude for detection each tone -32 (note 3) - -2 dbm referenced to 600 w minimum acceptable twist -8 - +4 db 60hz tolerance - - 0.8 v rms dial tone tolerance precise dial tone - - 0 db referenced to lower amplitude tone talk off mitel tape #cm7291 - 2 - hits digital outputs (except xout) 0 level, 400 m a load 0 - 0.5 v 1 level, 200 m a load v dd -0.5 - v dd v digital inputs 0 level 0 - 0.3v dd v 1 level 0.7v dd -v dd v supply current t a = 25 o c - 10 20 ma noise tolerance mitel tape #cm7291 (note 2) - - -12 db referenced to lowest amplitude tone input impedance v dd 3 v in 3 (v dd -10) 100k w //15pf 300k w - notes: 1. unused inputs must be connected to v dd or v ss as appropriate. 2. bandwidth limited (3khz) gaussian noise. 3. lower minimum available, please contact sales office. (-32dbm = 19.45mv rms , -2dbm = 0.615mv rms ) tw ist high to ne low tone --------------------------- - =
4-3 cd22204 functional block diagram ? 8 60hz reject clock generator chip clocks pre emp power regulator 4 8 v dd v ss voltage ref 697 770 852 941 1209 1336 1477 1633 band split filters zero crossing detectors bandpass filters amplitude detectors output decoder output register timing circuitry data strobe 12 2 1 14 13 3 data clear dv d1 d2 d4 d8 en analog in preprocessor 7 bs1 bs2 10 9 11 6 atb xen xin xout 1m note: pin numbers are for plastic dip. system functions analog in the analog in pin accepts the analog input. it is internally biased so that the input signal may be either ac or dc cou- pled, as long as it does not exceed the positive supply volt- age. proper input coupling is illustrated below. figure 1. analog in 7 v ss v dd 10pf >100k w (on chip) 270k w 33k w analog in 1500pf optional high frequency noise filter (f c = 3.9khz) audio input (+4dbm or 1.22v rms 0.01 m f cd22204e maximum) the cd22204 is designed to accept sinusoidal input wave- forms, but will operate satisfactorily with any input that has the correct fundamental frequency with harmonics that are at least 20db below the fundamental. crystal oscillator the cd22204 contains an on-board inverter with suf?cient gain to provide oscillation when connected to a low cost tele- vision color-burst (3.579545mhz) crystal. the crystal oscil- lator is enabled by tying xen high. the crystal is connected between xin and xout. a 1m w resistor is also connected between these pins in this mode. atb is a clock frequency output. other cd22204 devices may use the same fre- quency reference by tying their atb pins to the atb output of a crystal connected device. xin and xen of the auxiliary devices must then be tied high and low, respectively. up to ten devices may be run from a single crystal connected cd22204 as shown in figure 2.
4-4 cd22204 figure 2. crystal oscillator outputs d1, d2, d4, d8 and en outputs d1, d2, d4, d8 are cmos push-pull when enabled (en high) and open circuited (high impedance) when dis- abled by pulling en low. these digital outputs provide the hexadecimal code corresponding to the detected digit. the digital outputs become valid after a tone pair has been detected and they are then cleared when a valid pause is timed. the table below describes the hexadecimal codes. dv dv signals a detection by going high after a valid tone pair is sensed and decoded at the output pins d1, d2, d4, and d8. dv remains high until a valid pause occurs. n/c pin this pin has no internal connection and should be left ?oating. dtmf dialing matrix digital inputs and outputs all digital inputs and outputs of the dtmf receivers are rep- resented by the schematic below. only the analog in pin is different, and is described above. care must be exercised not to exceed the voltage or current ratings on these pins as listed in the maximum ratings section. figure 3. digital inputs and outputs input filter the cd22204 will tolerate total input noise of a maximum of 12db below the lowest amplitude tone. for most telephone applications, the combination of the high frequency attenuation of the telephone line and internal band limiting make special circuitry at the input to these receivers unnecessary. however, noise near the 56khz internal sampling frequency will be aliased (folded back) into the audio spectrum, so if excessive noise is present above 28khz, the simple rc ?lter shown below may be used to band limit the incoming signal. the cut off frequency is 3.9khz. figure 4. filter for use in extreme high frequency input noise environment table 1. output codes digit d8 d4 d2 d1 10001 20010 30011 40100 50101 60110 70111 81000 91001 01010 *1011 #1100 a1101 b1110 c1111 d0000 xen xen cd22204 10 9 6 11 atb xin 3.579545mhz v dd xout 1m 10 11 6 xin connected to v dd up to 10 devices cd22204 col 0 1209hz col 1 1336hz col 2 1477hz col 3 1633hz row 0 697hz row 1 770hz row 2 852hz row 3 941hz note: column 3 is for special applications and is not normally used in telephone dialing. 1 2 3 a 4 5 6 b 7 8 9 c * 0 # d v dd v ss cmos digital circuitry digital output digital input cd22204 33k w 0.0015 m f 270k w analog in noisy signal
4-5 all harris semiconductor products are manufactured, assembled and tested under iso9000 quality systems certi?cation. harris semiconductor products are sold by description only. harris semiconductor reserves the right to make changes in circuit design and/or speci?cations at any time without notice. accordingly, the reader is cautioned to verify that data sheets are current before placing orders. information furnished by harris is believed to be accurate and reliable. however, no responsibility is assumed by harris or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of harris or its subsidiaries. sales of?ce headquarters for general information regarding harris semiconductor and its products, call 1-800-4-harris north america harris semiconductor p. o. box 883, mail stop 53-210 melbourne, fl 32902 tel: 1-800-442-7747 (407) 729-4984 fax: (407) 729-5321 europe harris semiconductor mercure center 100, rue de la fusee 1130 brussels, belgium tel: (32) 2.724.2111 fax: (32) 2.724.22.05 asia harris semiconductor pte ltd. no. 1 tannery road cencon 1, #09-01 singapore 1334 tel: (65) 748-4200 fax: (65) 748-0400 semiconductor cd22204 noise will also be reduced by placing a grounded trace around xin and xout pins on the circuit board layout when using a crystal. it is important to note that xout is not intended to drive an additional device. xin may be driven externally; in this case, leave xout ?oating. timing waveforms figure 5. t on t off pause analog input d1, d2 d4, d8 tone burst 1 tone burst 2 t d t r t su t h dv parameter symbol min typ max units tone time for detection t on 40 - - ms for rejection t on - - 20 ms pause time for detection t off 40 - - ms for rejection t off - - 20 ms detect time t d 25 - 46 ms release time t r 35 50 ms data setup time t su 7- - m s data hold time t h 4.2 - 5 ms output enable time c l = 50pf, r l = 1k w - - 200 300 ns output disable time c l = 35pf, r l = 500 w - - 150 200 ns output rise time c l = 50pf - - 200 300 ns output fall time c l = 50pf - - 160 250 ns
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