HT9201A/b simple tone dialer selection table pin assignment patent number: 113235(r.o.c.), 5424740(u.s.a.) features operating voltage: 2.0v~5.5v low standby current 4 4 keyboard matrix 3.58mhz crystal or ceramic resonator four flash key times selectable for the ht9201b general description the HT9201A/b tone dialers are cmos lsis designed for telecommunication systems. the HT9201A is for mute output whereas the ht9201b is for flash output. both dialers pro- vide good performance for regular dtmf dial- ing with low distortion output and minimal ex- ternal components. HT9201A ht9201b f unction item mu t e f1,f2,f3,f4 f l as h t i me (ms ) ? ? 600/300/200/90 a,b ,c,d dt mf output ? ? xmut e package 16 dip 16 dip 1 3rd dec 97
keyboard information block diagram pin description pin name i/o internal connection description c1~ c4 r1~ r4 i/o cmos in/out these pins form a 4 4 keyboard matrix which can perform keyboard input detection and dialing specification setting functions. when the chip is in the standby mode the column group ( c1~ c4) remains low whereas the row group ( r1~ r4) is set high for key input detection. an inexpensive single contact 4 4 keyboard can be used as an input device. pressing a key connects a single column to a single row, and actuates the system oscillator which result in a dialing signal output. if more than two keys are pressed at a time, no response occurs. the key-in debounce time is 20ms. refer to the keyboard information for keyboard arrangement. HT9201A/b 2 3rd dec 97
pin name i/o internal connection description x1 i oscillator the system oscillator consists of an inverter, a bias resistor and the necessary load capacitor on chip. connecting a standard 3.579545mhz crystal or ceramic resonator to the x1 and x2 terminals can implement the oscillator function. the oscillator is turned off in the standby mode, and is actuated whenever a keyboard entry is detected. x2 o xmute o nmos out xmute is an nmos open drain structure pulled to vss during dialing signal transmission. otherwise, it is an open circuit. xmute is used to mute the speech circuit when transmitting the dial signal. mute o cmos out the output is low when no keypad input is entered and it becomes high during dialing sequence. the timing diagram is shown in the operation timing. flash o cmos out this pin is a cmos output structure from which the chip receives the flash key (f1~f4) signals to break the telephone line for a flash time. test i cmos in pull-high for ic chip test only vdd i positive power supply, 2.0v~5.5v for normal operation vss i negative power supply approximate internal connection circuits absolute maximum ratings* supply voltage ............................... C0.3v to 6v storage temperature ............... C50 c to 125 c input voltage ............... v ss C0.3v to v dd +0.3v operating temperature ............. C20 c to 75 c *note: stresses above those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only. functional operation of this device at these or any other conditions above those indicated in the operational sections of this specification is not implied and exposure to absolute maximum rating conditions for extended periods may affect device reliability. HT9201A/b 3 3rd dec 97
electrical characteristics (ta=25 c) symbol parameter test conditions min. typ. max. unit v dd conditions v dd operating voltage 2 5.5 v i dd operating current 2.5v keypad entry no load 0.6 2ma i stb standby current 2.5v no load, no entry 1 m a v il input low voltage v ss 0.2v dd v v ih input high voltage 0.8v dd v dd v i xmo xmute leakage current v xmute =12v no entry 1 m a i olxm xmute sink current 2.5v v xmute =0.5v 1 ma i oh1 keypad pin source current 2.5v v oh =0v C4 C40 m a i ol1 keypad pin sink current 2.5v v ol =2.5v 200 400 m a t db key-in debounce time f osc =3.5795mhz 20 ms f osc system frequency crystal=3.5795mhz 3.5759 3.5795 3.5831 mhz tone mode electrical characteristics (f osc =3.5795mhz, ta=25 c) symbol parameter test conditions min. typ. max. unit v dd conditions v tdc dtmf output dc level 0.45v dd 0.7v dd v i tol dtmf sink current 2.5v v dtmf =0.5v 0.1 ma v tac dtmf output ac level row group, r l =5k w 0.12 0.155 0.18 vrms r l dtmf output load 2.5v thd C23db 5 k w a cr column pre-emphasis 2.5v row group=0db 1 2 3 db thd dtmf signal distortion 2.5v r l =5k w C30C23db thd (distortion) (db) = 20 log ( ? ````````````````` v1 2 + v2 2 + ? + vn 2 ? ```````` ` vi 2 + vh 2 ) vi, vh: row group and column group signals v1, v2, ... vn: harmonic signals (bw=300hz~3500hz) HT9201A/b 4 3rd dec 97
timing diagrams functional description keyboard matrix c1~ c4 and r1~ r4 form a keyboard matrix. the keyboard arrangement for each of the ht9201 series are shown in the keyboard information . tone frequency tone name output frequency (hz) % error specified actual r1 697 699 +0.29% r2 770 766 C0.52% r3 852 847 C0.59% r4 941 948 +0.74% c1 1209 1215 +0.50% c2 1336 1332 C0.30% c3 1477 1472 C0.34% c4 1633 1645 +0.73% note: % error does not contain the crystal frequency drift key definition 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, * , #, a, b, c, d keys these are the dialing number input keys for normal operation. f1, f2, f3, f4 the flash keys can be selected with different flash times as shown in the following table. flash time selection table key flash time (ms) f1 600 f2 300 f3 200 f4 90 keyboard operation HT9201A/b 5 3rd dec 97
application circuits application circuit 1 HT9201A/b 6 3rd dec 97
application circuit 2 HT9201A/b 7 3rd dec 97
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