ILA1062

ILA1062 INTEGRAL | Alldatasheet

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TELEPHONE SPEECH NETWORK WITH DIALER INTERFACE

DESCRIPTION

The ILA1062 and ILA1062A are integrated circuits that perform all speech and line interface functions required in fully electronic telephone sets. They perform electronic switching between dialing and speech. The ICs operates at line voltage down to 1.6 V DC (with reduced performance) to facilitate the use of more telephone sets connected in parallel. All statements and values refer to all versions unless otherwise specified. The ILA1062(ILA1062A) is packaged in a standard 16-pin plastic DIP and special plastic DIP with internal heatsink is also available.

FEATURES

• Low DC line voltage; operates down to 1.6V (excluding polarity guard)
• Voltage regulator with adjustable static resistance
• Provides a supply for external circuits
• Symmetrical high-impedance inputs (64 kΩ) for dynamic, magnetic or piezo-electric microphones
• Asymmetrical high-impedance input (32 kΩ) for electret microphones
• DTMF signal input with confidence tone
• Mute input for pulse or DTMF dialing - ILA1062: active HIGH (MUTE) - ILA1062A: active LOW (MUTE)
• Receiving amplifier for dynamic, magnetic or piezo-electric earpieces
• Large gain setting range on microphone and earpiece amplifiers
• Line loss compensation (line current dependent) for microphone and earpiece amplifiers
• Gain control curve adaptable to exchange supply
• DC line voltage adjustment facility PIN CONNECTION BT1062A LN GAS1 GAS2 OR GAR MIC- MIC+ STA B SLPE AG C REG VCC MUTE DTMF IR VEE 8 9 ILA1062A

Characteristic Symbol Test Condition Min Typ Max Unit Line Voltage V LN I line = 15mA 3.55 4.0 4.25 V Operating Line Current I line 2.0 V dc Normal Operation 11 140 mA with Reduced Performance 1 11 mA Internal Supply Current I CC V CC = 2.8V 0.9 1.35 mA Supply Voltage for Peripherals V CC I line= 15mA Ip= 1.2mA Ip= 0mA 2.2 2.2 2.7 3.4 V Voltage Gain G V microphone amplifier 44 52 dB receiving amplifier 20 31 dB Line loss compensation Gain Control DGV 5.8 dB Exchange Supply Voltage V exch 36 60 V Exchange Feeding bridge Resistance Rexch 0.4 1 k W BLOCK DIAGRAM SUPPLY AND REFERENCE CURRENT REFERENCE LOW VOLTAGE CIRCUIT CONTROL CURRENT ILA1062A (1) 91 4 1 5 8 16 + + LNVCC IR MIC+ dB MIC- DTMF MUTE VEE REG AGC STAB SLPE GAS2 GAS1 QR GAR (1) Pin 12 is active HIGH (MUTE) for ILA1062. Fig.1 Block diagram for ILA1062A

Supplies VCC, LN, SLPE, REG and STAB Power for the IC and its peripheral circuits is usually obtained from the telephone line. The supply voltage is delivered 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. dialing and control circuits. Decoupling of the supply voltage is performed by a capacitor between V CC and VEE . The internal voltage regulator is decoupled by a capacitor between REG and VEE. The DC current flowing into the set is determined by the exchange supply voltage Vexch , the feeding bridge resistance Rexch and the DC resistance of the telephone line Rline . The circuit has internal current stabilizer operating at a level determined by a 3.6 k ? resistor connected between STAB and VEE (see Fig.6). When the line current (Iline) is more than 0.5mA greater than the sum of the IC supply current (ICC) and the current drawn by the peripheral circuitry connected to VCC (Ip) the excess current is shunted to VEE via LN. The regulated voltage on the line terminal (V LN) can be calculated as: VLN = Vref + ISLPE x R9 VLN = Vref + {(Iline - ICC - 0.5 x 10-3A) - Ip} x R9 V ref is an internally generated temperature compensated reference voltage of 3.7V and R9 is an external resistor connected between SLPE and VEE. In normal use the value of R9 would be 20?. Changing the value of R9 will also affect microphone gain, DTMF gain, gain control characteristics, sidetone level, maximum output swing on LN and the DC characteristics (especially at the lower voltages). Fig.2 Equivalent impedance circuit Under normal conditions, when I SLPE >>ICC + 0.5mA + Ip, the static behaviour of the circuit is that of a 3.7V regulator diode with an internal resistance equal to that of R9. In the audio frequency range the dynamic impedance is largely determined by R1. Fig.2 show the equivalent impedance of the circuit. At line currents below 9mA the internal reference voltage is automatically adjusted to a lower value (typically 1.6V at 1mA). This means that more sets can be operated in parallel with DC line voltage (excluding the polarity guard) down to an absolute minimum voltage of 1.6V. At line currents below 9mA 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 ? (2 x 32k?) and its voltage gain is typically 52 dB (when R7 = 68k?; see Fig.6). Dynamic, magnetic, piezo-electric 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. Stability is ensured by two external capacitors, C6 connected between GAS1 and SLPE and C8 connected between GAS1 and VEE. The value of C6 is 100pF but this may be increased to obtain a first-order low-pass LN Rp R = 16.2 kp Ω Leq L = C3 x R9 x Req p Vref REG V CC VEE 100 Fµ 4.7 Fµ Ω

filter. The value of C8 is 10 times the value of C6. The cut-off frequency corresponds to the time constant R7 x C6. Input MUTE (ILA1062) When MUTE is LOW or open-circuit, the DTMF input is enable 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 enable dialing tones may be sent on to the line. The voltage gain from DTMF to LN is typically 25.5 dB (when R7=68k ?) 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 31dB (when R4 = 100k?). It can be adjusted between 20 and 31dB 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 (32dB) from the amplifier gain. Two external capacitors, C4 and C7, ensure stability. C4 is normally 100pF and C7 is 10 times the value of C4. The value of C4 may be increased to obtain a first-order low-pass filter. The cut-off frequency will depend on the time constant R4 x C4. 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 0.5mm diameter twisted-pair copper cable with a DC resistance of 176 ?/km and average attenuation of 1.2dB/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. Sidetone suppression The anti-sidetone network, R1//Z line, R2, R3, R8, R9 and Zbal suppresses the transmitted signal in the earpiece. Maximum compensation is obtained when the following conditions are fulfilled: R9 x R2 = R1 x R3 R8 Z R8 Z bal bal   x (1) Z ZR 8 bal bal + Z ZR 1 line line + (2) If fixed values are chosen for R1, R2, R3 and R9, then condition (1) will always be fulfilled when To obtain optimum sidetone suppression, condition (2) has to be fulfilled which results in:

Zbal = x Zline = k x Zline Where k is scale factor; k = The scale factor k, dependent on the value of R8, is chosen to meet the following criteria:

• compatibility with a standard capacitor from the E6 or E12 range for Zbal
• |Zbal//R8|<<R8 fulfilling condition (a) and thus ensuring correct anti-sidetone bridge operation
• |Zbal + R8|>>R9 to avoid influencing the transmit gain. In practise Zline varies considerably with the line type and length. The value chosen for Zbal should therefore be for an average line thus giving optimum setting for short or long lines. ABSOLUTE MAXIMUM RATING Characteristic Symbol Test Condition Min Typ Max Unit Positive Continuous Line Voltage VLN 12 V Repetitive Line Voltage During Switch-on or Line Interruption VLN(R) 13.2 V Repetitive Peak Line Voltage for a 1ms Pulse per 5s VLN(RM) R9 = 20 W; R10 = 13W; see Fig.6 28 V Line Current I line R9 = 20 W; note 1 140 mA Input Voltage on all other Pins V I -0.7 VCC+0.7 V Total Power Standard DIP P tot R9 = 20 W; note 2 0.58 W Dissipation DIP with heatsink 0.67 Operating Ambient Temperature TA -25 +75 oC Storage Temperature T stg -40 +125 oC Junction Temperature T j +125 oC Notes 1. Mostly dependent on the maximum required TA and on the voltage between LN and SLPE. 2. Calculated for the maximum ambient temperature specified and a maximum junction temperature of 125oC. (Thermal Resistance RJA = 85oC/W for standard DIP and RJA = 75oC/W for special DIP with heatsink). (1) TA=45oC; Ptot=0.94W (2) TA=55oC; Ptot=0.82W (3) TA=65oC; Ptot=0.71W (4) TA=75oC; Ptot=0.58W 4681 0 1 2 110 130 150 V - V ( V )LN SLPE I ( m A )LN (1) (2) (3) (4) (1) TA=45oC; Ptot=1.07W (2) TA = 55oC; Ptot=0.93W (3) TA=65oC; Ptot=0.80 W (4) TA=75oC; Ptot=0.67 W 4681 0 1 2 110 130 150 V - V ( V )LN SLPE I ( m A )LN (1) (2) (3) (4) Fig.3a Safe operating area(Standard DIP) Fig.3b Safe operating area (DIP with HS)

Iline = 11mA to mA; VEE = 0V; f = 800Hz; TA = 25 o C; unless otherwise specified. Characteristic Symbol Test Condition Min Typ Max Unit Voltage Drop over Circuit between LN and VEE VLN MIC inputs open-circuit Iline = 1mA Iline = 4mA Iline = 15mA Iline = 100mA Iline = 140mA 3.55 4.9 1.6 1.9 4.0 5.7 4.25 6.5 7.5 V Variation with Temperature |V LN/|T I line = 15mA -0.3 mV/ o C Voltage Drop over Circuit Between LN and V EE with External Resistor RVA VLN I line = 15mA RVA(LN to REG) = 68kW RVA(REG to SLPE) = 39kW 3.5 4.5 V Supply Current I CC V CC = 2.8V 0.9 1.35 mA Supply Voltage available for Peripheral Circuitry VCC I line = 15mA; Ip = 1.2mA Ip = 0mA 2.2 2.7 3.4 V Microphone inputs MIC- and MIC+ (pins 6 and 7) Input Impedance Differential i | between MIC- and MIC+ kW Single-ended MIC- or MIC+ to V EE 32 kW Common mode rejection ratio CMRR 82 dB Voltage Gain MIC+ or MIC- to LN G v I line = 15mA; R7 = 68kW 50.5 52.0 53.5 dB Gain Variation with Frequency referenced to 800Hz DG vf f = 300 and 3400 Hz ± 0.2 dB Gain Variation with Temperature referenced to 25 o C DGvT without R6; I line = 50mA; TA = -25 and +75 o C ± 0.2 dB DTMF Input (Pin 11) Input Impedance |Z i | 20.7 kW Voltage Gain from DTMF to LN G v I line = 15mA; R7 = 68kW 243.0 25.5 27.0 dB Gain Variation with Frequency referenced to 800Hz DGvf f = 300 and 3400 Hz ± 0.2 dB Gain Variation with Temperature referenced to 25 o C DGvT I line = 50mA; TA = -25 and +75 o C ± 0.2 dB Gain adjustment inputs GAS1 and GAS2 (Pins2 and 3) Transmitting Amplifier Gain variation by adjustment of R7 between GAS1 and GAS2 DGv -8 0 dB Sending amplifier output LN (Pin1) Output Voltage (RMS value) V LN(rms) THD = 10 % Iline = 4mA Iline = 15mA 1.7 0.8 2.3 V Noise Output Voltage (RMS value) V no(rms) I line = 15mA; R7 = 68kW; 200W between MIC- and MIC+; -69 dBmp Receiving amplifier input IR (Pin 10) Input Impedance |Z i | 21 kW Receiving amplifier output QR (Pin 4) Output Impedance |Z o | 4 W Voltage Gain from IR to QR Gv I line = 15mA; RL = 300W; (from pin 9 to pin 4) 29.5 31 32.5 dB Gain Variation with Frequency referenced to 800Hz DGvf f = 300 and 3400 Hz ± 0.2 dB Gain Variation with Temperature referenced to 25 o C DGvT without R6; I line = 50mA; TA = -25 and +75 o C ± 0.2 dB Output Voltage (RMS value) V o(rms) THD = 2%; sine wave drive; R4 = 100kW; Iline = 15mA; Ip = 0mA RL = 150W RL = 450W 0.22 0.3 0.33 0.48 V V

Characteristic Symbol Test Condition Min Typ Max Unit Output Voltage (RMS value) V o(rms) THD = 10%; R4 = 100kW; RL = 150W; Iline = 4mA 15 mV Noise Output Voltage (RMS value) V no(rms) I line = 15mA; R4 = 100kW; IR open-circuit R L = 300W 50 mV Gain adjustment input GAR (Pin 5) Receiving Amplifier Gain Variation by adjustment of R4 between GAR and QR DGv -11 0 dB Mute input (Pin 12) HIGH Level Input Voltage V IH 1.5 V CC V LOW Level Input Voltage V IL 0.3 V Input Current I MUTE 8 15 mA Reduction of Gain MIC+ or MIC- to LN TEA1062 TEA1062A DG v MUTE = HIGH MUTE = LOW dB Voltage Gain from DTMF to QR TEA1062 TEA1062A G v R4 = 100kW; R L = 300W MUTE = HIGH MUTE = LOW -17 -17 dB Automatic Gain Control Input AGC (Pin 15) Controlling the Gain from IR to QR and the Gain from MIC+, MIC- to LN Gain Control Range DG v R6 = 110kW (between AGC and VEE) Iline = 70mA 5.8 dB Highest Line Current for Maximum Gain I lineH 23 mA Lowest Line Current for Minimum Gain I lineL 61 mA 123 4 0.8 1.6 2.4 V( V )CC I (mA) p (1) (2) Fig.4 Typical current Ip available from VCC for peripheral circuitry. The supply possibilities can be increased by setting the voltage drop over the circuit V LN to a higher value be resistor RVA connected between REG and SLPE. VCC > 2.2V; Iline = 15mA at VLN = 4V; R1 = 620W; R9 = 20W (1) Ip = 2.1mA. Curve (1) is valid when the receiving or when MUTE = HIGH(ILA1062), MUTE = LOW(ILA1062A). (2) I p = 1.7mA. Curve (2) is valid when MUTE = LOW(ILA1062), MUTE = HIGH(ILA1062A) and the receiving amplifier is driven; Vo(rms) = 150mV, RL = 150W.

R9 = 20 Ω 40 60 80 120 140100

0 R6 =

I ( m A )line (dB) V Fig. 5 Variation of gain as a function of the line current with R6 as a parameter TABLE 1 Values of resistor R6 for optimum line-loss compensation at various values of exchange supply voltage (Vexch) and exchange bridge resistance (Rexch ); R9 = 20W. Vexch (V) 400 Rexch (W) 600 R exch (W) 800 R exch (W) 1000 R exch (W) R6 (k W) 36 100 78.7 - - 48 140 110 93.1 82 60 - - 120 102 PINNING Pin Symbol Description

1 LN Positive Line Terminal

2 GAS1 Gain Adjustment; Transmitting Amplifier

3 GAS2 Gain Adjustment; Transmitting Amplifier

4 QR Non-inverting Output; Receiving Amplifier

5 GAR Gain Adjustment; Receiving Amplifier

6 MIC- Inverting Microphone Input

7 MIC+ Non-inverting Microphone Input

8 STAB Current Stabilizer

9 V EE Negative Line Terminal

10 IR Receiving Amplifier Input

11 DTMF Dual-tone Multi-Frequency Input

12 MUTE Mute Input (see note 1)

13 V CC Positive Supply Decoupling

14 REG Voltage Regulator Decoupling

15 AGC Automatic Gain Control Input

16 SLPE Slope (DC resistance) Adjustment

Note 1. Pin 12 is active HIGH (MUTE) for ILA1062

APPLICATION INFORMATION

(2x) BZX79 C12 BAS11 (2x) R10 13Ω 130k Ω 3.92k Ω 620Ω QR IR LN MIC- SLPE telephone line GAS1 GAS2 REG AGC R7R8 Zbal 390Ω 100 pF 1 nF R( R )VA 16-14 STAB MUTE DTMF ILA1062A 100 Fµ 4.7 Fµ 3.6 kΩ Ω (1) 98321 416 15 from dial VEE VCC 1 nF 100pF 100 nF The diode bridge, the Zener and and the the circuit A different arrangement required dialling The DC line can be set to a higher R VA (REG to SLPE). R10 limit the current across, line transients. protection register voltage value by (1) Pin 12 is active HIGH (MUTE) for BT1062. and control circuits into, voltage during is for pulse or recall. the resistor Fig. 6 Typical application of ILA1062A, with piezo-electric earpiece and DTMF dialling