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BL34118 http://www.belling.com.cn - 1 - 8/15/2006 total 11 pages wrote by 2006 voice switched speakerphone circ uit BL34118 the BL34118 voice switched speakerphone circuit incorporates the necessary amplifiers, attenuators, level detectors, and control algorithm to form the heart of a high quality hands-free speakerphone system. included are a microphone ampl ifier with adjustable gain and mute control, transmit and receive attenuators which operate in a complementary manner, level detectors at both input and output of both attenuators, and backgroun d noise monitors for both the transmit and receive channels. a dial tone detector prevents the dial to ne from being attenuated by the receive background noise monitor circuit. also included are two line d river amplifiers, which can be used to form a hybri d network in conjunction with an external coupling tr ansformer. a high-pass filter can be used to filter out 60hz noise in the receive channel, or for other fun ctions. a chip disable pin permits powering down th e entire circuit to conserve power on long loops wher e loop current is at a minimum. the BL34118 may be operated from a power supply, o r it can be powered from the telephone line, requiring typically 5.0 ma. the BL34118 can be inte rfaced directly to tip and ring (through a coupling transformer) for stand-alone operation, or it can b e used in conjunction with a handset speech network and/or other features of a feature phone. improved attenuator gain range: 52 db between trans mit and receive low voltage operation for line-powered applications (3.0 C 6.5v) 4-point signal sensing for improved sensitivity background noise monitors for both transmit and rec eive paths microphone amplifier gain set by external resistors C mute function included chip disable for active/standby operation on board filter pinned-out for user defined functio n dial tone detector to inhibit receive idle mode dur ing dial tone presence standard 28-pin plastic dip package and soic packag e available compatible with bl34119 speaker amplifier pin connections( top view ) fo fi cd vcc hto+ hto- hti txo txi mco mci mut vlc ct gnd cpr rli1 rlo1 tlo1 tli1 rxo rxi rli2 rlo2 tlo2 tli2 cpt vb 12 3 4 56 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15
BL34118 http://www.belling.com.cn - 2 - 8/15/2006 total 11 pages wrote by 2006 pin descrption pin name description 1 fo filter output. output impedance is less than 5 0 ohms. 2 fi filter input. input impedance is greater than 1.0 mohm. 3 cd chip disable. a logic low (<0.8v) sets normal o peration. a logic high (>2.0v) disables the ic to conserve power. input impedance is nominally 90 k w . 4 vcc a supply voltage of +2.8 to +6.5 volts is requ ired, at ? 5.0 ma. as vcc falls from 3.5 to 2.8 volts, an agc circuit reduces the receive attenuator gain by ? 25 db (when in the receive mode). 5 hto+ output of the second hybrid amplifier. the g ain is internally set at C1.0 to provide a differen tial output, in conjunction with hto-, to the hybrid tra nsformer. 6 hto- output of the first hybrid amplifier. the ga in of the amp is set by external resistors. 7 hti input and summing node for the first hybrid a mplifier. dc level is ? vb. 8 txo output of the transmit attenuator. dc level i s approximately vb. 9 txi input to the transmit attenuator. max. signal level is 350 mvrms. input impedance is ? 10 k w . 10 mco output of the microphone amplifier. the gain of the amplifier is set by external resistors. 11 mci input and summing node of the microphone amp lifier. dc level is ? vb. 12 mut mute input. a logic low (<0.8v) sets normal o peration. a logic high (>2.0v) mutes the microphone amplifier without affecting the rest of the circuit . input impedance is nominally 90 k w . 13 vlc volume control input. when vlc = vb, the receive attenuator is at maximum gain when in the receive mode. when vlc = 0.3vb, the receive gain is do wn 35 db. does not affect the transmit mode. 14 ct an rc at this pin sets the response time for t he circuit to switch modes. 15 vb an output voltage ? vcc/2. this voltage is a system as ground, and bias es the volume control. a filter cap is required. 16 cpt an rc at this pin sets the time constant for t he transmit background monitor. 17 tli2 input to the transmit level detector on the mike/speaker side. 18 tlo2 output of the transmit level detector on th e mike/speaker side, and input to the transmit background monitor. 19 rlo2 output of the receive level detector on the mike/speaker side. 20 rli2 input to the receive level detector on the mike/speaker side. 21 rxi input to the receive attenuator and dial ton e detector. max input level is 350 mvrms. input impedance is ? 10 k w . 22 rxo output of the receive attenuator. dc level i s approximately vb. 23 tli1 input to the transmit level detector on the line side. 24 tlo1 output of the transmit level detector on th e line side. 25 rlo1 output of the receive level detector on the line side, and input to the receive background mon itor. 26 rli1 input to the receive level detector on the line side. 27 cpr an rc at this pin sets the time constant for t he receive background monitor. 28 gnd ground pin for the entire ic.
BL34118 http://www.belling.com.cn - 3 - 8/15/2006 total 11 pages wrote by 2006 block diagram volume control power amplifier speaker microphone mute tx attenuator rx attenuator attenuator control background noise monitor level detectors level detectors background noise monitor bias filter -1.0 agc zb ring tip vcc chip disable dial tone detector absolute maximum ratings parameter value units supply voltage (pin 4) -1.0, +7.0 vdc voltage at cd (pin 3), mut (pin 12) -1.0, vcc + 1.0 vdc voltage at vlc (pin 13) -1.0, vcc + 0.5 vdc voltage at txi (pin 9), rxi (pin21), fi (pin 2) -0.5, vcc + 0.5 vdc storage temperature range -65 to +150 o c recommended operating limits parameter min typ max units supply voltage (pin 4) 3.5 - 6.5 vdc cd input (pin 3), mut input (pin 12) 0 - vcc vdc i vb (pin 13) - - 500 m a vlc ( pin 13) 0.3xvb - vb vdc attenuator input signal voltage (pins 9, 21) 0 - 350 mvrms microphone amplifier, hybrid amplifier gain 0 - 40 db load current @ rxo, txo (pins 8, 22) @ mco (pin 10) @ hto-, hto+ (pins 6, 5) 0 0 0 - - - 2.0 1.0 5.0 ma ambient operating temperature range -20 - +60 c
BL34118 http://www.belling.com.cn - 4 - 8/15/2006 total 11 pages wrote by 2006 electrical characteristics (t a =+25 c, vcc=5.0v, cd 0.8v, unless noted) parameter symbol min typ max units power supply vcc supply current (vcc=6.5v, cd=0.8v) (vcc=6.5v,cd= 2.0v) icc - - 5.5 600 8.0 800 ma m a cd input resistance (vcc=vcd=6.5v) cd input voltage C high _ low r cd v cdh v cdl 50 2.0 0 90 - - - vcc 0.8 k w vdc vdc v b output voltage (vcc = 3.5v) (vcc = 5.0v) v b - 1.8 1. 3 2.1 - 2.4 vdc v b output resistance (i vb = 1.0 ma) r ovb - 400 - w v b power supply rejection ratio (c vb = 220 uf, f = 1.0khz) psrr - 54 - db attenuators (t a = +25 c) receive attenuator gain (f = 1.0 khz, vlc = vb) rx mode, rxi = 150 mvrms (vcc = 5.0v) rx mode, rxi = 150 mvrms (vcc = 3.5v) gain change C vcc = 3.5v versus vcc = 5.0v agc gain change C vcc = 2.8v versus vcc = 5.0v idle mode, rxi = 150 mvrms range (rx to tx mode) g rx g rx d g rx1 d g rx2 g rxi d g rx3 +4.0 +4.0 -0.5 - -22 49 +6.0 +6.0 0 -25 -20 52 +8.0 +8.0 +0.5 -15 -17 54 db volume control range (rx mode, 0.3vb < vlc < vb) v cr 27 35 - db rxo dc voltage (rx mode) v rxo - vb - vdc d rxo dc voltage (rx to tx mode) d v rxo - 10 150 mv rxo high voltage (iout = - 1.0ma rxi = vb + 1.5v) v rxoh 3.7 - - vdc rxo low voltage ( iout = - 1.0 ma, rxi = vb C 1.0, outp ut measured with respect to vb) v rxol - -1.5 -1.0 vdc rxi input resistance (rxi < 350 mvrms) r rxi 7.0 10 14 k w transmit attenuator gain (f = 1.0 khz) tx mode, txi = 150 mvrms idle mode, txi = 150 mvrms range (tx to rx mode) g tx g txi d g txi +4.0 -22 49 +6.0 -20 52 +8.0 -17 54 db txo dc voltage (tx mode) v txo - vb - vdc d txo dc voltage (tx to rx mode) d v txo - 30 150 mv txo high voltage (iout = -1.0 ma txi = vb +1.5v) v txoh 3.7 - - vdc txo low voltage (iout = +1.0 ma, txi = vb C 1.0v, outp ut measured with respect to vb) v txol - -1.5 -1.0 vdc txi input resistance (txi < 350 mvrms) r txi 7.0 10 14 k w gain tracking ( g rx + g tx , @ tx, idle, rx) g tr - 0.1 - db
BL34118 http://www.belling.com.cn - 5 - 8/15/2006 total 11 pages wrote by 2006 attenuator control (t a = +25 c) ct voltage ( pin 14 C vb) rx mode (vlc = vb) idle mode tx mode v ct - - - +240 0 -240 - - - mv ct source current (switching to rx mode) i ctr -85 -60 -40 m a ct sink current (switching to tx mode) i ctt +40 +60 +85 m a ct slow idle current i cts - 0 - m a ct fast idle internal resistance r fi 1.5 2.0 3.6 k w vlc input current i vlc - -60 - na dial tone detector threshold v dt 10 15 20 mv microphone amplifier (t a = +25 c, v mut 0.8v, a vcl = 31 db unless otherwise noted) output offset (vmco C vb, feedback r = 180 k w ) mco vos -50 0 +50 mvdc open loop gain (f < 100 hz) a volm 70 80 - db gain bandwidth gbw m - 1.0 - mhz output high voltage (iout = -1.0ma, vcc = 5.0v) v mcoh 3.7 - - vdc output low voltage (iout = +1.0ma) v mcol - - 200 mvdc input bias current (@ mci) i bm - -40 - na muting ( d gain) (f = 1.0khz, v mut = 2.0 v) (300 hz < f < 10 khz) gmt -55 - - -68 - - db mut input resistance ( vcc = v mut = 6.5v) r mut 50 90 - k w mut input C high v muth 2.0 - vcc vdc mut input C low v mutl 0 - 0.8 vdc distortion ( 300 hz < f < 10 khz) thd m - 0.15 - % hybrid amplifier (t a = +25 c) hto- offset (vhto- - vb, feedback r = 51 k w ) h vos -20 0 +20 mvdc hto- to hto+ offset (feedback r = 51 k w ) hb vos -30 0 +30 mvdc open loop gain ( hti to hto-, f < 100 hz) a volh 60 80 - db gain bandwidth gbw h - 1.0 - mhz closed loop gain ( hto- to hto+) a vclh -0.35 0 +0.35 db input bias current ( @ hti) i bh - -30 - na hto- high voltage ( iout = -5.0 ma) v ht-h 3.7 - - vdc hto- low voltage ( iout = +5.0 ma) v ht-l - - 250 mvdc hto+ high voltage ( iout = -5.0 ma) v ht+h 3.7 - - vdc hto+ low voltage ( iout = +5.0 ma) v th+l - - 450 mvdc distortion ( 300 hz < f < 10 khz, see figure 1) thd h - 0.3 - %
BL34118 http://www.belling.com.cn - 6 - 8/15/2006 total 11 pages wrote by 2006 level detectors and background noise monitors (t a = +25 c) transmit-receive switching threshold ( ratio of current at rli1 + rli2 to 20 ua at tli1 + tli2 to switch from tx to rx) i th 0.8 1.0 1.2 source current at rlo1, rlo2, tlo1, tlo2 i lso - -2.0 - ma sink current at rlo1, rlo2, tlo1, tlo2 i lsk - 4.0 - m a cpr, cpt output resistance ( iout = 1.5 ma) r cp - 35 - w cpr, cpt leakage current i cplk - -0.2 - m a filter (t a = +25 c) voltage offset at fo (v fo C vb, 220 k w from v b to fi) fo vos -200 -90 0 mv fo sink current i fo 150 260 400 m a fi bias current i fi - -50 - na system distortion (t a = +25 c) rx mode ( from fi to rxo, fo connected to rxi) thd r - 0.5 3.0 % tx mode ( from mci to hto-/hto+, includes tx attenu ator) thd t - 0.8 3.0 % 1. all currents into a devices pin are positive, th ose out of a pin are negative, algebraic convention rather than magnitude is used to define limits. r - -- - + ++ + - -- - + ++ + r vb vb vin hti 10 k 0.1 1200 ohm 51 k x1 instr. amplifier to dist. analyzer hto- hto+ figure 1 C hybrid amplifier distortion test
BL34118 http://www.belling.com.cn - 7 - 8/15/2006 total 11 pages wrote by 2006 figure 2 C attenuator gain versus vct figure 3 C level det ector dc transfer characteristics figure 4 C level detector ac transfer figure 5 C level detector a c transfer characteristics characteristics versus frequency figure 6 C receive attenuator versus volume figure 7 C receive attenuation gain control versus vcc gain (db) vct C vb (mv) dc input current (ua) output change (mv) output change (mv) input signal (mvrms) f, frequency (hz) output change from 1.0khz(mv) gain (db) gain change (db) vlc / vb vcc (volts)
BL34118 http://www.belling.com.cn - 8 - 8/15/2006 total 11 pages wrote by 2006 figure 8 C microphone amplifier and 1 st hybrid figure 9 C input characteristics @ cd, mut amplifier open loop gain and phase figure 10 C supply current versus supply figure 11 C vb outpu t characteristics voltage figure 12 C vb power supply rejection versus figure 13 C power supply rejection of the frequency and vb capacitor microphone and hybrid amplifiers input current (ua) input voltage (volts)
BL34118 http://www.belling.com.cn - 9 - 8/15/2006 total 11 pages wrote by 2006 figure 14 C typical output swing versus vcc temperature characteristics parameter typical value @ 25 c typical change C20 to +60 c vcc supply current (cd = 0.8 v) 5.0 ma - 0.3 %/ c vcc supply current (cd = 2.0 v) 400 m a -0.4 %/ c vb output voltage (vcc = 5.0 v) 2.1 v +0.8 %/ c attenuator gain (max gain ) +6.0 db 0.0008 db/ c attenuator gain (max attenuation) -46 db 0.004 db/ c attenuator input resistance (@ txi, rxi) 10 k w + 0.6 %/ c dial tone detector threshold 15 mv +20 m v/ c ct source, sink current 60 m a -0.15 %/ c microphone, hybrid amplifier offset 0 mv 4.0 m v/ c transmit-receive switching threshold 1.0 0.02 %/ c sink current at rlo1, rlo2, tlo1, tlo2 4.0 m a -10 na/ c closed loop gain (hto- to hto+) 0 db 0.001 %/ c
BL34118 http://www.belling.com.cn - 10 - 8/15/2006 total 11 pages wrote by 2006 application circuit fo fi cd vcc hto+ hto- hti txo txi mco mci mut vlc ct gnd cpr rli1 rlo1 tlo1 tli1 rxo rxi rli2 rlo2 tlo2 tli2 cpt vb 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 + - + - + - + - + - rx attenuat or tx attenuat or attenuator control + - + - + - agc bnm bnm +1 vb vb vb vb vb vb vb vcc vb filter r r dtd vcc vcc vcc mute 100k 47uf 2.0uf 2.0 uf 120k 5.0uf 220uf 2.0uf 100k 47uf 2.0uf vb volume control 20k 9.1k vb 220k 4700u f 10k 56k 0.1 0.05 0.1 51k rhf rhi 10k 0.1 5.1k 0.1 5.1k 0.1 270pf 180k rmf 5.1k 0.2 bl34119 43 1 6 7 8 5 vb 5.1k 0.05 200pf 110k rl 10k 0.1 1000uf tip ring hook switch disable 1n4733 5.1v 820 0.05 300 0.01 vb 20uf vcc 0.02 mike assembly package dimension
BL34118 http://www.belling.com.cn - 11 - 8/15/2006 total 11 pages wrote by 2006 unit: inches (mm) sop 28

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