tone/pulse dialer with redial S5T5820C 1 introduction the S5T5820C is a dtmf/pulse switchable dialer with a 32-digit redial which can be done using a slide switch. all necessary dual-tone frequencies are derived from a 3.579545 mhz tv crystal or ceramic resonator providing very high accuracy and stability. the required sinusoidal wave form for each individual tone is digitally synthesized on the chip. the generated wave form has very low total harmonic distortion (7% max). a voltage reference is generated on the chip which is stable over the operating voltage and temperature range and regulates the single levels of the dual tone to meet telephone industry specifications. cmos technology is applied to this device, for very low power requirements high noise immunity, and easy interface to a variety of telephones requiring external components. features tone/pulse switchable (slide switch) 32-digit capacity for redial automatic mix redialing ( last number dial ) pulse dtmf with multiple auto access pause pabx auto-pause for 3.5 sec. 4 x 4 or ( 2 of 8 ) keyboard available two key single tone operation operating voltage : 2.0 to 5.5v numbers dialed manually after redial are cascadable and stored as additional numbers for next redialing uses inexpensive tv crystal or ceramic resonator (3.579545mhz) make/break ratio (33.3 / 66.6) pin selectable touch key hooking (604ms) low standby current improved emi characteristics improved redial memory quality ordering information device package operating temperature S5T5820C03-d0b0 18 ? dip ? 300a ? 20 c to + 70 c S5T5820C03-s0b0 20 ? sop ? 375 18 ? dip ? 300a 20 ? sop ? 375
S5T5820C tone/pulse dialer with redial 2 block diagram keyboard logic redial memory 32 digit input logic control logic osc dtmf generator ouput logic r1 r2 r3 r4 c4 c3 c2 c1 x?mute osc in osc out tone out v ss v dd dp hs m/b mds
tone/pulse dialer with redial S5T5820C 3 pin configuration 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 s1t5820c r1 r2 r3 r4 hs m/b mds osc in osc out c4 c3 c2 c1 dp tone out v ss v dd x ? mute (18 dip) 1 2 3 4 5 6 7 8 9 12 13 14 15 16 17 18 19 20 S5T5820C r1 r2 r3 r4 hs m/b mds osc in osc out c4 c3 c2 c1 dp tone out nc nc x ? mute 10 v dd 11 v ss (20 sop)
S5T5820C tone/pulse dialer with redial 4 arrangement of keyboard tone frequencies * keyboard description 1 2 3 4 5 6 hk 7 8 9 p * 0 # rd r1 r2 r3 r4 c1 c2 c3 c4 input specified actual % error r1 697 699.1 + 0.31 r2 770 766.2 ? 0.49 r3 852 847.4 ? 0.54 r4 941 948.0 + 0.74 c1 1209 1215.7 + 0.57 c2 1336 1331.7 ? 0.32 c3 1477 1471.9 ? 0.35 hk p rd : hooking (604ms) : pause (3.5 second) : redial
tone/pulse dialer with redial S5T5820C 5 pin description pin no symbol description 1 ? 4 15 ? 18 r1 ? r4 c1 ? c4 keyboard (r1 , r2 , r3 , r4 , c1 , c2 , c3 , c4 ) these inputs can be interfaced to an xy matrix keyboard. c1 ? c4 & r1 ? r4 are set to low at on hook (hs = high). c1 ? c4 key inputs are set to low and r1 -r4 are set to high at off hook (hs = low) which enables the key-input operation. the oscillator starts running when a key-press is detected. scanning signals are presented at both column and row inputs (typ: 437hz) until the input key is released. key inputs are compatible with standard 2-of-8 form or a single-contact keyboard. debouncing is provided to avoid false entry (typ: 4ms). 5 hs hook switch this input detects the state of the hook switch contact. off hook corresponds to v ss condition. on hook corresponds to v dd condition. 6 m/b make/break ratio this input provides the selection of the make/break ratio (33.3: 66.6/40:60) when m/b is connected to v dd /v ss . 7 mds mode select input pulse/dtmf mode is selected as shown is the following table. initial mode means the state after going off hook ( hs v ss ) 8 ? 9 osc in osc out oscillator input/output these pins are provided to connect an external 3.58mhz crystal. oscillator starts (at off hook) and is sustained until pulse or dtmf signals are finished. 10 ? 11 v dd , v ss power supply inputs. the device is designed to be operated on 2.0v to 5.5v 12 tone out dtmf signal output when a valid keypress is detected in dtmf mode, appropriate low and high group frequencies are generated which hybrid the dual tone output. tone out is off state in pulse mode. 13 x ? mute x ? mute output (n channel open drain) 14 dp dial pulse out dp : the normal output will be on during break and off during make at off hook. the output will be off at on hook. mds mds mds mds inital mode switching entry mode v dd pulse mds input = v ss v ss to n e n / a hs hs hs hs x?mute x?mute x?mute x?mute output v dd on v ss normally off on during pulse and dtmf dialing
S5T5820C tone/pulse dialer with redial 6 absolute maximum ratings electrical characteristics (v ss = 0v, v dd = 3.5v, f xtal = 3.579545mhz, ta = 25 c, unless otherwise specified) characteristic symbol value unit supply voltage v dd 6.0 v input voltage v i v ss - 0.3, v dd + 0.3 v output voltage v o v ss - 0.3, v dd + 0.3 v output voltage v o (dxm) v dd (dp , x ? mute , mute ) v tone output current i o (tone) 50 ma power dissipation p d 500 mw operating temperature t opr ? 20 to + 70 c storage temperature t stg ? 40 to + 125 c characteristic symbol test conditions min. typ. max. unit operating voltage range v dd ? 2.0 ? 5.5 v memory retention voltage v mr ? 1.0 ?? v memory retention current i mr hs = v dd = 1.0v ? 0.05 0.1 a operating current i dd (pulse) mds = v dd one selected hs = vss, all outputs unloaded ? 0.1 0.3 ma i dd (tone) mds = v ss ? 0.4 0.7 standby current i sb hs = v ss no key selected. all outputs unloaded ? 10 50 a output current i ol1 dp ,v dd = 3.5v 1.7 5.0 ? ma i ol2 x?mute v dd = 2.5v 0.5 1.5 ? input voltage v ih r1 - r4 , c1 - c3 , hs , m/b 0.8v dd ? v dd v v il mds v ss ? 0.2v dd input current i l1 v dd = 3.5v, v in = 0v r1 - r4 ?? 50 a i l2 v dd = 2.5v, v in = 0v ?? 30 valid key entry time t kd ? ? 23 ? ms key release time t kr ? ? 5 ? ms tone duration t td ? ? 110 ? ms tone interdigit pause time t tidp ? ? 110 ? ms column and row scanning frequency f cr ? ? 437 ? hz auto access pause time t ap ? ? 3.5 ? sec tone output v d(tone) row tone only v dd = 2.5v, r l = 5k ? ? 14.0 ?? 12.0 dbv v dd = 3.5v, r l = 5k ? ? 14.0 ?? 12.0 ratio of column to row tone db cr v dd = 3.5v 1.0 2.0 3.0 db distortion thd v dd = 3.5v ?? 7% tone output delay time t d(tone) ? ? 1.5 ? ms
tone/pulse dialer with redial S5T5820C 7 application information keyboard operation single mode operation pulse mode operation the pulse mode is defined by the initial mode after going off hook and latched at d1 key entry. this is the condition under mds = v dd . tone mode operation the tone mode is defined by the initial mode after going off hook and latched at d1 key entry. this is the condition under mds = v ss . manual dialing with automatic access pause multiple pause key entries can be accepted and stored in the redial memory, each as a digit. each p key provides 3.5 seconds pause time, but the p key entry as the first digit after going off hook is ignored. the * key can also be used as a pause key in the pulse mode. pause (2) can be cancelled with the p or rd key during pause time in redialing. d = any numeric key. redialing up to 32 digits can be dialed with the rd key. the rd key is disabled while pulse or dtmf signals are transmitted. when more than 32 digits are stored, redial is also inhibited. the # key can be used as the rd key in the pulse mode. inhibiting redial redial can be inhibited by pressing the rd key twice after dtmf or pulse signals are transmitted. off hook d1 ..... dn off hook d1 ..... dn off hook d p d1 ..... dn off hook rd off hook d1 ..... dn rd rd
S5T5820C tone/pulse dialer with redial 8 pulse/tone switchable operation mode switching by mds input the pulse mode is initially defined mds = v dd . mode switching to the dtmf mode can be accepted by mds = v ss . the dtmf mode will be set up after the pulse mode is finished. in this mode, digits dn + 1 ... dn + m are transmitted from tone out as dtmf signals by pressing the corresponding keys. if no p key is contained serially before or after mode switching, the following condition is obtained. if digit dn+1 is depressed after the pulse mode is finished, the dtmf mode will be set up after last the pulse signal ( dn ) is generated. in this mode,digits dn+1 ... dn+m are transmitted from tone out as dtmf signals by pressing the corresponding keys. if digit dn+1 is pressed during dialing pulse signals. what happens? when the dtmf mode is set, the hold state will be set after last pulse signal dn is finished. mdo will flash to indicate this hold state, dn+1 ... dn+m are stored in redial memory as dtmf data and not transmitted from tone out. when it is ready to transmit dtmf data in redial memory, the rd or p key is pressed to reset this hold state and dn+1 ... dn+m data are serially transmitted. off hook d1 ..... dn p switching mds to vss dn+1 ... dn+m pulse mode dtmf mode off hook d1 ..... dn switching mds to vss dn+1 ... dn+m pulse mode dtmf mode (dn+1 pause)
tone/pulse dialer with redial S5T5820C 9 tone mode timing (mds = v ss ) pulse mode timing (mds = v dd ) key input 43 rd tone 43 x? mute t tidp t tidp t tidp hs key input dp x ? mute 4 3 t kr t b t m t pidp
S5T5820C tone/pulse dialer with redial 10 timing diagram (for switching mode operation by mds input) hs key input dp tone out mds d 23p switching ms = v ss *2 1 8 t pa t tidp t td x? mute t pa : 3.5 sec
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