unisonic technologies co., ltd tea1110a linear integrated circuit www.unisonic.com.tw 1 of 9 copyright ? 2015 unisonic technologies co., ltd qw-r108-014.d low voltage versatile telephone transmission circuit with dialler interface ? description the utc tea1110a is a versatile telephone transmission circuit providing full speech and line interface functions in electronic telephone sets. this device works at a line voltage which can be as low as 1.6v dc (with reduced performance) to enable parallel connection of telephone sets. it also realizes electronic switching between speeches and dialling. the utc tea1110a is ideal for applications, such as line powered telephone sets, cordless telephones, and fax machines, answering machines. ? features * low dc line voltage; operates down to 1.6v (excluding voltage drop over external polarity guard) * voltage regulator with adjustable dc voltage * provides a supply for external circuits * symmetrical high impedance inputs (64k ? ) for dynamic, magnetic or piezo-electric microphones * asymmetrical high impedance input (32k ? ) for electric microphones * dtmf input with confidence tone * mute input for pulse or dtmf dialling * receiving amplifier for dynamic, magnetic or piezo-electric earpieces * agc line loss compensation for microphone and earpiece amplifiers. dip-14 sop-14 ? ordering information ordering number package packing lead free halogen free tea1110al-d14-t tea1110ag-d14-t dip-14 tube - tea1110ag-s14-r sop-14 tape reel
tea1110a linear integrated circuit unisonic technologies co., ltd 2 of 9 www.unisonic.com.tw qw-r108-014.d ? marking dip-14 sop-14 ? pin configuration mic- mic+ v ee qr gar v cc agc 1 2 3 4 5 6 7 14 13 12 11 10 9 8 ir mute dtmf nc reg ln slpe ? pin description pin no. pad no. symbol description 1 1 ln positive line terminal 2 2 slpe slope (dc resistance) adjustment 3 3 reg line voltage regulator decoupling 4 4 nc not connected 5 5 dtmf dual-tone multi-frequency input 6 6 mute mute input to select speech or dialing mode (active low) 7 7 ir receiving amplifier input 8 8 agc automatic gain control/line loss compensation 9 9 mic- inverting microphone amplifier input 10 10 mic+ non-inverting microphone amplifier input 11 11 v ee negative line terminal 12 12 qr earpiece amplifier output 13 13 gar earpiece amplifier gain adjustment 14 14 v cc supply voltage for internal circuit
tea1110a linear integrated circuit unisonic technologies co., ltd 3 of 9 www.unisonic.com.tw qw-r108-014.d ? absolute maximum ratings parameter symbol ratings unit positive continuous line voltage v ln v ee -0.4 ~ 12 v repetitive line voltage during switch-on or line interruption v ee -0.4 ~ 13.2 v maximum voltage on all pins v n ( max ) v ee -0.4 ~v cc +0.4 v maximum line current (r slpe =20 ? ) i line 140 ma power dissipation (ta=75c) dip-14 p d 588 mw sop-14 384 mw junction temperature t j 125 c ambient temperature t opr -25~+75 c storage temperature t stg -40~+125 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? thermal data parameter symbol ratings unit junction to ambient dip-14 ja 85 c/w sop-14 130 c/w note: mounted on epoxy board ? electric characteristics (ta=25c, unless otherwise specified) (i line =15ma, v ee =0v, r slpe =20 ? , agc pin connected to v ee , z line =600 ? ,f=1khz) parameter symbol conditions min typ max unit supplies (pins vln, v cc , slpe and reg) stabilized voltage between ln and slpe v ref 3.1 3.35 3.6 v dc line voltage v ln i line =1ma 1.6 v i line =4ma 2.3 v i line =15ma 3.35 3.65 3.95 v i line =140ma 6.9 v dc line voltage with an external resistor rva v ln(exr) r va(slpe-reg) = 27k ? 4.4 v dc line voltage variation with temperature referred to 25 c v ln(t) ta = -25 ~ +75 c 30 mv internal current consumption i cc v cc = 2.9 v 1.3 1.48 ma supply voltage for peripherals v cc i p =0ma 2.9 v equivalent supply voltage resistance r cc int i p =0.5ma 550 620 ? microphone amplifier (pins mic+ and mic-) voltage gain from mic+/mic- to ln g vt x v mic =4mv (rms) 42.7 43.7 44.7 db gain variation with frequency referred to 1khz g vtx(f) f =300~3400 hz 0.2 db gain variation with temperature referred to 25c g vtx(t) ta =-25~+75 c 0.3 db common mode rejection ratio cmrr 80 db maximum sending signal (rms value) v ln(max) (rms) i line =15ma; thd=2% 1.4 1.7 v i line =4ma, thd=10% 0.8 v noise output voltage at pin ln, pins mic+/mic- shorted through 200 ? v notx -78.5 dbmp
tea1110a linear integrated circuit unisonic technologies co., ltd 4 of 9 www.unisonic.com.tw qw-r108-014.d ? electric characteristics(cont.) parameter symbol conditions min typ max unit receiving amplifier (pins ir, qr and gar) voltage gain from ir to qr g vr x v ir = 4mv (rms) 32 33 34 db gain variation with frequency referred to 1khz g vrx(f) f = 300~3400 hz 0.2 db gain variation with temperature referred to 25c g vrx(t) ta = -25 ~ +75 c 0.3 db gain voltage reduction range g vrxr external resistor connected between gar and qr 14 db maximum receiving signal (rms value) v o(rms) i p =0ma sine wave drive r l = 50 ? , thd =2% 0.25 v i p = 0ma sine wave drive r l =450 ? , thd =2% 0.35 noise output voltage at pin r (rms value) v norx(rms) g vrx =33db, ir open-circuit, r l =150 ? -87 dbvp automatic gain control (pin agc) gain control range for microphone and receiving amplifiers with respect to i line =15ma g vtrx i line = 85ma 5.9 db highest line current for maximum gain i start 23 ma lowest line current for minimum gain i stop 56 ma dtmf amplifier (pin dtmf) voltage gain from dtmf to ln g vdtmf v dtmf = 20mv (rms) mute = low 24.1 25.3 26.5 db gain variation with frequency referred to 1khz g vdtmf(f) f = 300~3400hz 0.2 db gain variation with temperature referred to25c g vdtmf(t) ta = -25 ~ +75 c 0.4 db voltage gain from dtmf to qr (confidence tone) g vct v dtmf = 20mv (rms) r l = 150 ? -15 db mute function (pin mute) low level input voltage v il v ee -0.4 v ee +0.3 v high level input voltage v ih v ee +1.5 v cc +0.4 v input current mute i 1.5 a gain reduction for microphone and receiving amplifiers g vtrxm mute = low 80 db
tea1110a linear integrated circuit unisonic technologies co., ltd 5 of 9 www.unisonic.com.tw qw-r108-014.d ? application information circuit typical application of the utc tea1110a in sets with pulse dialling or flash facilities -+ ir ln qr gar mic + mic - slpe reg agc v ee vcc dtmf mute r cc 619 + z bal r ast3 390 r ast2 3.92k r ast1 130k rprotect 10 a/b b/a telephone line vdr 95v r pd2 470k r pd3 1m r pd4 470k r pd5 470k bc547 r pd6 68k pd input 1 nf utc tea1110a + bc547 bsn254 bc558 bf473 bzx79c10 4 bas11 c gars c gar 100pf c ir r slpe 20 r limit 3.9 bzx79c10 470k r pd1 signal from dial and control circuits supply for peripheral circuits c reg 4.7 f c vcc 100 f
tea1110a linear integrated circuit unisonic technologies co., ltd 6 of 9 www.unisonic.com.tw qw-r108-014.d ? functional description supply (pins ln, slpe, v cc and reg) the utc tea1110a and its peripheral circuit derive the power s upply from telephone line (see fig.1). the ic generates a stabilized reference voltage (v ref ) between pins ln and slpe. the voltage at pin slpe is proportional to the line current. v ref is temperature compensated and can be adjus ted by means of an external resistor (r va ). v ref is set to 3.35 v, which can be increased by connec ting rva between pins reg and slpe (see fig.2) and be decreased by connecting rva between pins reg and ln. the voltage at pin reg is used by the internal regulator to generate v ref and is decoupled by, which is connected to v ee . this c reg capacitor converted into an equivalent inductance (see section ?set impedance?) realizes the set impedance conversion from its dc value (r slpe ) to its ac value (r cc in the audio-frequency range). in the following formula, the most appropriate value for r slpe is 20 ? . the changing of rslpe will affect the dc characteristics; furthermore, it can influence the microph one and dtmf gains, the gain c ontrol characteristics, the side tone level and the maximum output swing on the line. the voltage at pin ln is: v ln = v ref +r slpe i slpe i slpe = i iine -i cc -i p -i* where: i line = line current i cc = current consumption of the ic i p = supply current for peripheral circuits i* = current consumed between ln and v ee . r cc + slpe reg + v ee 2 3 11 + vd 1 from pre amp i cc i* v cc 14 ln + - + i p - - fig 1. supply configuration. r exch v exch l line r line utc tea1110a i sh i slpe r slpe 20 ? 619 ? c reg 4.7 f cv cc 100 f peripheral circuits
tea1110a linear integrated circuit unisonic technologies co., ltd 7 of 9 www.unisonic.com.tw qw-r108-014.d ? functional description(cont.) 6.0 3.0 5.0 4.0 10 4 10 5 10 6 10 7 (1) influence of rva on v ref (2) v ref without influence of rva fig.2 reference voltage adjustment by r va (1) (2) r va ( ) the internal circuitry of the utc tea1110a is supplied from pin v cc which can be used to supply peripheral circuits such as dialling or control circuits. this voltage supply is derived from the line voltage by means of a resistor (r cc ) and it must be decoupled by a capacitor cv cc . the v cc voltage depends on the current consumed by the ic and the peripheral circuits as shown by the formula :( r cc int is the internal equivale nt resistance of the voltage supply, and irec is the current consumed by the output stage of the earpiece amplifier)) v cc = v cc0 - r cc int (i p -i rec ) v cc0 = v ln -r cc i cc (see also figs 3 and 4). the dc line current flowing into the set is determined by the exchange supply voltage (vexch), the feeding bridge resistance (rexch), the dc resistance of the telephone line (rline) and the reference voltage (v ref ). the internal reference voltage (generating v ref ) would be automatically adjusted to a lower value when the line currents drop below 7.5ma. therefore, more sets can work in parallel with dc line voltages (excluding the polarity guard) down to 1.6v (absolute minimum volt age). at currents below 7.5ma, the ci rcuit has limited sending and receiving levels. this is called the low voltage area. 2.5 2 0.5 0 01 2 3 4 1.5 1 (1) (2) vcc (v) (1) with r va resistor. (2) without r va resistorl vcc v ee rccint vcco irec peripheral circuit ip + fig.3 typical current i p available from v cc for peripheral circuits at i line =15ma. fig.4 v cc supply voltage for peripherals
tea1110a linear integrated circuit unisonic technologies co., ltd 8 of 9 www.unisonic.com.tw qw-r108-014.d ? functional description(cont.) set impedance the dynamic impedance is mainly determined by the rcc resistor within the audio frequency range. the equivalent impedance of the ci rcuit is shown in fig.5. rcc 619 vcc cvcc 100 f + + rp reg c reg r slpe l eq vref slpe ln v ee l eq =c reg r slpe rp rp=internal resistance rp=15.5k fig.5 equivalent impedance between ln and v ee 20 4.7 f microphone amplifier (pins mic+ and mic-) the utc tea1110 a has symmetrical microphone inputs. the input impedance between pin mic+ and pin mic- is 64k ? (2 32k ? ). on this microphone amplifie r, automatic gain control is used for line loss compensation. receiving amplifier (pins ir, gar and qr) the receiving amplifier has one input (ir) and one ou tput (qr). the input impedance between pin ir and pin v ee is 20k ? . connecting an external resistor rgar between pi ns gar and qr can decrease the voltage gain within 14db from pin ir to pin qr. the two external capacitors cgar (connected between pins gar and qr) and cgars (connected between gar and v ee ) ensure stability, the cgar capacitor provides a first- order low-pass filter. the cut-off frequency corresponds to the time constant cgar (r garint // r gar ). and the r garint is the internal resistor connected between pins gar and qr which sets a 125 kw typ gain. the condition c gars = 10 c gar is required to ensure stability. the output voltage of the receiv ing amplifier is for continuous wave dr ive specially. the maximum output swing depends on the dc line voltage, the r cc resistor, the i cc current consumption of the circuit, the ip current consumption of the peripheral ci rcuits and the load impedance. on this receiving amplifier automatic gain control is used for line loss compensation. automatic gain control (pin agc) the utc tea1110a performs automatic line loss compensation. the automatic gain control varies both the gain of the microphone amplifier and receiving amplifier in a ccordance with the dc line current within 5.9 db (which corresponds approximately to a line length of 5 km for a 0.5 mm diameter twisted-pair copper cable with a dc resistance of 176 ? /km and an average attenuation of 1.2db/km). the ic can be used with different config urations of feeding brid ge (supply voltage and bridge resistance) by the means of connecting an external re sistor ragc between pins agc and v ee . the line currents i start and i stop can be increased by this resistor (the ratio between i start and i stop is not affected by the resi stor). when pin agc is in the open-circuit condition, the agc function is inactive. mute function (pin mute mute) the mute function performs the switching between t he speech mode and the dialling mode. when the mute is in a low level, the dtmf input is active and the microphone and receiving amplifiers inputs are inactive. when the mute is in a high level, the microphone and receiving amplif iers inputs are active while the dtmf input is inactive. the input includes a pull-up resistor. dtmf amplifier (pin dtmf) when the dtmf amplifier is inactive, dialling tones that can be heard in the earpiece at a low level may be sent on line. the utc tea1110a has an asymmetrical dtmf input. the input impedance between dtmf and v ee is 20k ? . the automatic gain control has no effect on the dtmf amplifier.
tea1110a linear integrated circuit unisonic technologies co., ltd 9 of 9 www.unisonic.com.tw qw-r108-014.d ? functional description(cont.) sidetone suppression the utc tea1110a anti-side tone network consisting of r cc //zline, rast1, rast2, rast3, r slpe and zbal (see fig.6) suppresses the transmitted signal in the earpiece. maximum compensat ion is obtained under the following conditions: r slpe rast1=r cc (rast2+rast3) ) r 1 rast ( )) r + 3 rast ( 2 rast ( = k slpe slpe zbal= kziine the scale factor k is mainly for the compatibility with a standard capacitor from the e6 or e12 range for zbal. zline varies considerably with the line type and the line le ngth in practice. therefore, the zbal value should be set to be an average line length which gives appropriate side tone suppression with short and long lines. the suppression also depends on the accuracy of the ma tch between zbaland the impe dance of the average line. the receiving signal is to be attenuated 32db by the ant i-side tone network from the line before it enters the receiving amplifier, and the attenuation is almost constant over the whole audio frequency range. im ra st1 zbal ras t 3 slpe rast2 ir r cc v ee zline r s lpe ln zir fig.6 equivalent circuit of utc tea1110a anti-sidetone bridge utc assumes no responsib ility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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