unisonic technologies co., ltd mc34018 linear integrated circuit www.unisonic.com.tw 1 of 8 copyright ? 2014 unisonic technologies co., ltd qw-r108-006.e voice switched speaker-phone circuit ? description the utc mc34018 speaker-phone integrated circuit includes all the active circuitry and control functions to implement a high quality hands-free telephone system. the circuit includes a microphone amplifier, a speaker amplifier, level detectors, a background sound level monitoring system in both the transmit and receive channels and an attenuation system which can control the transmit and receive levels as well as the background level. the applications include household and office speaker-phones, intercom systems, hand free kit for mobile phones, and others. ? features * chip select pin for power conservation (active/standby mode). * integrated all necessary active circuitry for a hand-free telephone into one single chip. * operating under wide dynamic range through signal compression technology. * build-in voltage regulators illuminate external regulators for lining operation. * monitoring system for background noise level. * background sound level compensation for transmit and receive levels as well as the background level. * power audio amplifier for typical 100mw output (into 25 ? ) with peak limiting for speaker to minimize distortion. * volume control function for exte rnal volume control circuit. ? ordering information order number package packing lead free halogen free - MC34018G-D28-T dip-28 tube mc34018l-e28-t mc34018g-e28-t sdip-28 tube - mc34018g-r28-t ssop-28 tube - mc34018g-r28-r ssop-28 tape reel - mc34018g-s28-t sop-28 tube - mc34018g-s28-r sop-28 tape reel
mc34018 linear integrated circuit unisonic technologies co., ltd 2 of 8 www.unisonic.com.tw qw-r108-006.e ? marking package marking sop-28 ssop-28 dip-28 sdip-28 ? pin configuration 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 rr rtx txi txo tli tlo rli rlo mci mco cp1 cp2 xdi skg rrx rxi rxo acf v lc xdc gnd v b v cc ski cs agc v+ sko
mc34018 linear integrated circuit unisonic technologies co., ltd 3 of 8 www.unisonic.com.tw qw-r108-006.e ? pin description pin no. pin name description 1 rr a resistor to ground provides a referenc e current for the transmit and receive attenuators 2 rtx a resistor to ground determines the nominal gain of the transmit a ttenuator, the transmit channel gain is inversely proportional to rtx resistance. 3 txi transmit attenuator input, in put resistance is nominally 5.0k ? . 4 txo transmit attenuator output, the txo output signal drivers the input of transmit level detcetor, as well as the external ci rcuit which drivers the telephone line. 5 tli transmit level detector input. an external re sistor ac coupled to the tli pin sets the detection level. decreasing this resistor in creases the sensitivity to transmit channel signals. 6 tlo transmit level detector output. the external resistor and capacitor set the time the comparator will hold the system in the transmit mode after speech ceases. 7 rli receive level detector input. an external re sistor ac coupled to the rli pin sets the detection level. decreasing this resistor increa ses the sensitivity to receive channel signals. 8 rlo receive level detector output. the external resistor and capacitor set the time the comparator will hold the system in the receive mode after speech ceases. 9 mci microphone amplifier input. input impedance is nominally 10k ? and the dc bias voltage is approximately equal to vb 10 mco microphone amplifier output. the mic am p gain is internally set at 34db (50v/v). 11 cp1 a parallel resistor and capacitor connected between this pin and vcc holds a voltage corresponding to the background noise leve l. the transmit detector compares the cp1 voltage with the speech signal from cp2. 12 cp2 a capacitor at this pin peak detects the speech signals for comparison with the background noise level held at cp1. 13 xdi input to the transmit detector system. the micr ophone amplifier output is ac coupled to the xdi pin through an external resistor. 14 skg high current ground pin for the speaker amplifie r output stage. the skg voltage should be within 10mv of the ground voltage at pin 22. 15 sko speaker amplifier output. the sko pin will source and sink up to 100ma when ac coupled to the speaker. the speaker amplifier gain is internally set at 34db (50v/v). 16 v+ input dc supply voltage. v+ can be powered from tip and ring if an ac decoupling inductor is used to prevent loading ac line signals. t he required v+ voltage is 6.0v to 11v (7.5v nominal) at 7.0ma. 17 agc a capacitor from this pin to vb stabilizes t he speaker amplifier gain control loop, and additionally controls the attack and decay time of this circuit. the gain control loop limits the speaker amplifier input to prevent clipping at sko. the internal resistance at agc pin is nominally 110k ? . 18 cs digital chip select input. when at a logic "0" (<0.7v) the vcc regulator is enabled. when at a logic "1" (>1.6v),the chip is in the standby mode drawing 0.5ma.an open cs pin is a logic "0".input impedance is nominally 140k ohms. the input voltage should not exceed 11v. 19 ski input to the speaker amplif ier. input impedance is nominally 20k ? . 20 vcc a 5.4v regulated output which powers all circui ts except the speaker amplifier output stage. vcc can be used to power external circuitry such as a microprocessor(3.0ma max.) a filter capacitor is required. the utc mc34018 can be powered by a separate regulated supply by connecting v+ and vcc to a voltage between 4. 5v and 6.5v while maintaining cs at a logic "1". 21 vb an output voltage equal to approximately v cc/2 which series as an analog ground for the speakerphone system. up to 1.5ma of exte rnal load current may be sourced from vb. output impedance is 250 ohms. a filter capacitor is required. 22 gnd ground pin for the ic(exc ept the speaker amplifier)
mc34018 linear integrated circuit unisonic technologies co., ltd 4 of 8 www.unisonic.com.tw qw-r108-006.e ? pin description(cont.) pin no. pin name description 23 xdc transmit detector output. a resistor and capacitor at his pin hold the system in the transmit mode during pauses between words or phr ases. when the xdc pin voltage decays to ground, the attenuators switch fr om the transmit mode to idle mo de. the internal resistor at xdc is nominally 2.6k ohms(see fig.1). 24 vlc volume control input>connecting this pin to the sl ider of a variable resistor provides receive mode volume control. the vlc pin voltage should be less than or equal to vb. 25 acf attenuator control filter. a capac itor connected to this pin r educes noise transient as the attenuator control switches level of attenuation. 26 rxo receive attenuator output. normally this pin is ac coupled to the input of the speaker amplifier. 27 rxi receive attenuator input. i nput impedance is nominally is 5.0k ? . 28 rrx a resistor to ground determines the nominal gain of the receive attenuator. the receive channel gain is directly proportional to the rrx resistance. ? block diagram speaker
mc34018 linear integrated circuit unisonic technologies co., ltd 5 of 8 www.unisonic.com.tw qw-r108-006.e ? absolute maximum ratings (t a =25 ? c, voltage referred to pin 22.) parameter symbol ratings unit v+ terminal voltage (pin 16) +12, -1.0 v cs (pin 18) +12, -1.0 v speaker amplifier ground(pin 14) +3.0, -1.0 v v lc (pin 24) +v cc , -1.0 v storage temperature t stg -65 ~ +150 ? 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. ? recommended operation conditions parameter symbol ratings unit v+ terminal voltage (pin 16) +6.0 ~ +11 v cs (pin 18) 0 ~ +11 v v lc (pin 24) 0.55v b ~ v b v receive signal(pin 27) 0 ~ 250 mvrms microphone signal(pin 9) 0 ~ 5.0 mvrms speaker amplifier ground (pin 14) -10 ~ +10 mvdc i cc (pin 20) 0 ~ 3.0 ma ambient temperature t a -20 ~ +60 ? c ? temperature characteristics (-20 ~+60 ? c) parameter pin typ change unit v+ supply current ( v+ 11v,pin 18 = 0.7v ) 16 -0.2 %/ ? c v+ supply current(v+ 11v,pin 18 = 1.6v ) 16 -0.4 %/ ? c v cc voltage( v+ = 7.5v ) 20 +0.1 %/ ? c attenuator gain ( max and min setting ) 0.003 db/ ? c delta rxo,txo voltage 4,26 0.24 %/ ? c speaker amp gain 15,19 0.001 db/ ? c microphone amp gain 9,10 0.4 db/ ? c microphone amp input resistance 9 +0.4 %/ ? c tx-rx switching threshold (20 ? a) 5,7 0.2 na/ ? c ? electrical characteristi cs (referred to fig.1) parameter symbol test conditions min typ max unit supply voltages v cc voltage v cc v+=7.5v 4.9 5.4 5.9 vdc line regulation ? v ccln 6.5v mc34018 linear integrated circuit unisonic technologies co., ltd 6 of 8 www.unisonic.com.tw qw-r108-006.e ? electrical characteristics (cont.) parameter symbol test conditions min typ max unit rxo voltage (rx mode) v rxo 1.8 2.3 3.2 mv delta rxo voltage (switch from rx to tx mode) ? v rxo 100 mv rxo sink current (rx mode) i rxol 75 a rxo source current (rx mode) i roxh 1.0 3.0 ma rxi input resistance r rxi 3.5 5.0 8.0 k ? volume control range v cr rx attenuator gain, rx mode, 0.6v b mc34018 linear integrated circuit unisonic technologies co., ltd 7 of 8 www.unisonic.com.tw qw-r108-006.e ? test circuit v b v b v b v b v b 19 26 28 27 4 1 2 3 25 21 8 7 6 5 9 10 13 12 11 23 18 16 20 22 17 15 14 24 vb regulator attenuator control receive/transmit comp transmit attenuator receive attenuator speaker amp peak limiter vcc regulator transmit detector comp vth (36mv) receive amp transmit log amp mic amp vcc vcc rlo vb vlc acf txi rr txo rrx rxi rtx rxo ski skg sko agc gnd vcc 5.4v v+ cs xdc cp1 cp2 xdi mco mci tli tlo rti 25 4.3k 18k 30k 91k 47 f 0.05 f 0.01 f 0.1 f 0.1 f 4.7 f 47 f 1.0 f vcc 24k 20k 2.2m vb 0.068 f 4.7k 1.0 f 2.2m 0.068 f 3.3k 2k 0.1 f 0.05 f 0.068 f 4.7k 4.7 f47 f 100k 47 f 200k 1000 f 47 f 1.0 f vcc 10k 12k 59k 33k 56k 500 500 dc line input receive input mic transmit output 2.6k v b fig 1 test circuit ? basic line powered speakerphone 3 10 13 4 5 11 25 17 16 9 15 14 24 21 20 2 1 28 26 19 12 18 7 27 23 6 8 22 txi mco xdi txo tli cp1 acf agc v+ cs rli rxi gnd rlo tlo xdc cp2 ski rxo rrx rr rtx vcc vb vlc skg sko mci 20k 24k 91k 30k 18k 4.3k 200k 47 f 47 f 0.01 f 0.05 f 4.7 f 4.7 f 1.0 f 1.0 f 2.2m 2.2m 47 f 0.05 f 2k 4.7k 0.1 f 0.068 f 0.068 mf 3.3k 100k 1.0 f 47 f 4.7 f vcc 0.068 f 3.3k 0.1 f 0.01 f 22k 47k 470k 4700pf 470k 4700pf 0.05 f 15k 1000 f 47k 8.2k 0.068 f 0.01 f 2.2k 470k 10 f 33k 47k 8.2k 8.2k 47k 6.8k 2.7k 220k 68k 0.01 f 0.01 f 4.7k 0.1 f mic speaker volume control hook switch s1 t r s2 utc mc34018 v b v b v b fig 2
mc34018 linear integrated circuit unisonic technologies co., ltd 8 of 8 www.unisonic.com.tw qw-r108-006.e utc assumes no responsibility 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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