BL1062A1 BELLING | Alldatasheet
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http://www.belling.com.cn - 1 - 8/25/2006 Total 7 Pages Wrote by 2006 Low voltage transmission circuits with dialer interface 1. GENERAL DESCRIPTION The BL1062A1 is integrated circuits that perform all speech and line interface functions required in fully electronic telephone sets. It performs electronic switching between dialling and speech. The ICs operate at line voltage down to 1.6 V DC (with reduced performance) to facilitate the use of more telephone sets connected in parallel. BL1062A1 improves the EMC performance in-circuit that can enhance the telephone sets’ EMC. 2. FEATURES /circle6 Low DC line voltage; operates down to 1.6 V (excluding polarity guard) /circle6 Voltage regulator with adjustable static resistance /circle6 Provides a supply for external circuits /circle6 Symmetrical high-impedance inputs (64 Κ Ω ) for dynamic, magnetic or piezoelectric microphones /circle6 Asymmetrical high-impedance input (32 Κ Ω) for electret microphones /circle6 DTMF signal input with confidence tone /circle6 Mute input for pulse or DTMF dialling, active LOW (MUTE) /circle6 Receiving amplifier for dynamic, magnetic or piezoelectric earpieces /circle6 Large gain setting ranges on microphone and earpiece amplifiers /circle6 Line loss compensation (line current dependent) for microphone and earpiece amplifiers /circle6 Gain control curve adaptable to exchange supply /circle6 DC line voltage adjustment facility /circle6 Enhanced EMC performanc 3. BLOCK DIAGRAM Fig. 1 Block Diagram
http://www.belling.com.cn - 2 - 8/25/2006 Total 7 Pages Wrote by 2006 4. Pin Configurations, Definitions SYMBOL PIN DESCRIPTION LN 1 positive line terminal GAS1 2 gain adjustment; transmitting amplifier GAS2 3 gain adjustment; transmitting amplifier QR 4 non-inverting output; receiving amplifier GAR 5 gain adjustment; receiving amplifier MI Χ− 6 Inverting microphone input MIC+ 7 non-inverting microphone input NC 8 NC VEE 9 Negative line terminal IR 10 Receiving amplifier input DTMF 11 dual-tone multi-frequency input MUTE 12 mute input (see note 1) VCC 13 positive supply decoupling REG 14 voltage regulator decoupling AGC 15 automatic gain control input SLPE 16 slope (DC resistance) adjustment 5. Function Description Supplies VCC , LN, SLPE, REG Power for the IC and its peripheral circuits is usually obtained from the telephone line. The supply voltage is derived from the line via a dropping resistor and regulated by the IC. The supply voltage VCC may also be used to supply external circuits e.g. dialling and control circuits. Decoupling of the supply voltage is performed by a capacitor between VCC and VEE . The internal voltage regulator is decoupled by a capacitor between REG and V EE . The DC current flowing into the set is determined by the exchange supply voltage V exch, the feeding bridge resistance Rexch and the DC resistance of the telephone line Rline . At line currents below 9 mA the internal reference voltage is automatically adjusted to a lower value (typically 1.6 V at 1 mA). This means that more sets can be operated in parallel with DC line voltages (excluding the polarity guard) down to an absolute minimum voltage of 1.6 V. At line currents below 9 mA the circuit has limited sending and receiving levels. The internal reference voltage can be adjusted by means of an external resistor (R VA ). This resistor when connected between LN and REG will decrease the internal reference voltage and when connected between REG and SLPE will increase the internal reference voltage. Microphone inputs MIC+ and MIC − − − − and gain pins GAS1 and GAS2 The circuit has symmetrical microphone inputs. Its input impedance is 64 k Ω (2 x 32 k Ω ) and its voltage gain is typically 52 dB (when R7 = 68 k Ω , see Figures 2 and 3). Dynamic, magnetic, piezoelectric or electret (with built-in FET source followers) can be used. The gain of the microphone amplifier can be adjusted between 44 dB and 52 dB to suit the sensitivity of the transducer in use. The gain is proportional to the value of R7, which is connected between GAS1 and GAS2.
http://www.belling.com.cn - 3 - 8/25/2006 Total 7 Pages Wrote by 2006 Input MUTE When MUTE is LOW or open-circuit, the DTMF input is enabled and the microphone and receiving amplifier inputs are inhibited. The reverse is true when MUTE is HIGH. MUTE switching causes only negligible clicking on the line and earpiece output. If the number of parallel sets in use causes a drop in line current to below 6 mA the DTMF amplifier becomes active independent to the DC level applied to the MUTE input. Dual-tone multi-frequency input DTMF When the DTMF input is enabled dialling tones may be sent on to the line. The voltage gain from DTMF to LN is typically 25.5 dB (when R7 = 68 k Ω ) and varies with R7 in the same way as the microphone gain. The signalling tones can be heard in the earpiece at a low level (confidence tone). Receiving amplifier IR, QR and GAR The receiving amplifier has one input (IR) and a non-inverting output (QR). The IR to QR gain is typically 31 dB (when R4 = 100 k Ω ). It can be adjusted between 20 and 31 dB to match the sensitivity of the transducer in use. The gain is set with the value of R4, which is connected between GAR and QR. The overall receive gain, between LN and QR, is calculated by subtracting the anti-sidetone network attenuation (32 dB) from the amplifier gain. The output voltage of the receiving amplifier is specified for continuous-wave drive. The maximum output voltage will be higher under speech conditions where the peak to RMS ratio is higher. Automatic Gain Control input AGC Automatic line loss compensation is achieved by connecting a resistor (R6) between AGC and V EE . The automatic gain control varies the gain of the microphone amplifier and the receiving amplifier in accordance with the DC line current. The control range is 5.8 dB which corresponds to a line length of 5 km for a 0.5 mm diameter twisted-pair copper cable with a DC resistance of 176 Ω /km and average attenuation of 1.2 dB/km). Resistor R6 should be chosen in accordance with the exchange supply voltage and its feeding bridge resistance. The ratio of start and stop currents of the AGC curve is independent of the value of R6. If no automatic line-loss compensation is required the AGC pin may be left open-circuit. The amplifiers, in this condition, will give their maximum specified gain. Enhanced EMC performance The input pins BL1062A1 is added RC filters to improve the EMC performance, so the telephone sets which used BL1062A1 are easily to handle the EMC design. LIMITING VALUES SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT VLN positive continuous line voltage − 12 V VLN(R) repetitive line voltage during switch-on or line interruption − 13.2 V VLN(RM) repetitive peak line voltage for a 1 ms pulse per 5 s R9 = 20 Ω ; R10 = 13 Ω ; see Fig.6 − 28 V Iline line current R9 = 20 Ω − 140 mA Ptot total power dissipation R9 = 20 Ω − 600 mW Tamb operating ambient temperature −25 +75 oC Tstg storage temperature −40 +125 oC
http://www.belling.com.cn - 4 - 8/25/2006 Total 7 Pages Wrote by 2006 6. CHARACTERISTICS I line = 11 to 140 mA; V EE = 0 V; f = 800 Hz; T amb =25 oC; unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT VLN voltage drop over circuit between LN and V EE MIC inputs open-circuit I line = 1 mA Iline = 4 mA Iline = 15 mA Iline = 100 mA 3.55 4.9 1.6 1.9 4.0 5.7 4.25 6.5 V V VLN Voltage drop over circuit bewteen LN and V EE Iline = 15 mA; R VA (LN to REG)=68K Ω R VA (LN to SLPE)=39K Ω 3.5 4.5 ICC supply current VCC = 2.8 V − 0.9 1.35 mA VCC supply voltage available for peripheral circuitry Iline = 15 mA; MUTE = LOW I p = 1.2 mA MUTE = LOW I p = 0 mA 2.2 2.5 2.7 3.4 4.5 3.8 V V V V |Zi| Input impedance between MIC- and MIC+ Between MIC- and MIC+ 64 KΩ CMRR Common mode rejection ratio 82 dB G v MIC voltage gain MIC+ or MIC − to LN Iline = 15 mA; R7 = 68 k Ω Iline = 100 mA; R7 = 68 k Ω 50.5 44.0 52.0 45.5 54.5 47.0 dB dB △Gvf Gain variation with frequency reference to 800Hz F=300 and 3400 Hz ±0.2 dB △GvT Gain variation with temperature reference to 25 ℃ Without R6;I line =50mA; Tamb =－25 and +75 ℃ ±0.2 dB |Zi| Input impedance of DTMT 20.7 KΩ G v DTMF voltage gain from DTMF to LN Iline = 15 mA; R7 = 68 k Ω 24.0 25.5 27.0 dB △Gvf Gain variation with frequency reference to 800Hz F=300 and 3400 Hz ±0.2 dB △GvT Gain variation with temperature reference to 25 ℃ Without R6;I line =50mA; Tamb =－25 and +75 ℃ ±0.2 dB VLN(rms) output voltage (RMS value) THD = 10% I line = 15 mA 1.7 2.3 − V |Zi| Input impedence of receiving amplifier 21 KΩ G v voltage gain from IR to QR Iline = 15 mA; R L = 300 Ω Iline = 100 mA; R L = 300 Ω 29.5 24.5 32.5 27.5 dB dB △Gvf Gain variation with frequency reference to 800Hz F=300 and 3400 Hz ±0.2 dB △GvT Gain variation with temperature reference to 25 ℃ Without R6;I line =50mA; Tamb =－25 and +75 ℃ ±0.2 dB Vo(rms) output voltage (RMS value) THD = 2%; sine wave drive; R4 = 100 k Ω ; I line =15 mA; Ip =0 mA R L = 150 Ω R L = 450 Ω 0.22 0.3 0.33 0.48 V V
http://www.belling.com.cn - 5 - 8/25/2006 Total 7 Pages Wrote by 2006 Vo(rms) output voltage (RMS value) THD = 10%; R4 = 100 k Ω ; Iline =15 mA; R L = 150 Ω V △G V MIC- or MIC+ to LN MUTE=Low 70 dB △G V Voltage gain from DTMT to QR R4=100k Ω; R L=300 Ω MUTE=Low -17 dB △G V Controlling the gain from IR to QR and the gain from MIC+,MIC- to LN gain control range R6=110k Ω (bewteen A GC and V EE ) Iline =70mA -5.8 dB IlineH Hightest line current for maximum gain 23 mA IlineL Lowest line current for maximum gain 61 mA
http://www.belling.com.cn - 6 - 8/25/2006 Total 7 Pages Wrote by 2006 Fig2 Test circuit for defining BL1062A1 voltage gain of MIC+, MIC- and DTMF inputs Fig3 Test circuit for defining BL1062A1 voltage gain of receiving amplifier
http://www.belling.com.cn - 7 - 8/25/2006 Total 7 Pages Wrote by 2006 7. APPLICATION CIRCUITS Fig4 Typical application of BL1062A1