TEA7530 MONITOR AMPLIFIER PRELIMINARY DATA LOW VOLTAGE POWER: 100mW AT 5V ANTIDISTORTION SYSTEM FOR LOW CURRENT LINES DESCRIPTION This 8 pins IC is designed for monitor telephone set and provides: a) Signal amplification for monitoring b) Antidistortion by automatic gain adaptation. MINIDIP SO-8 ORDERING NUMBERS: TEA7530DP TEA7530FP ABSOLUTE MAXIMUM RATINGS Symbol Parameter Top Temperature Range VLS Supply Voltage ILS Supply Current for T > 300ms for T ≤ 300ms Value Minidip SO -20 to +70 -20 to +70 Unit °C 6 6 V 90 150 75 120 mA mA BLOCK DIAGRAM June 1993 1/11 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. TEA7530 PIN CONNECTION (top view) PIN FUNCTION N° Symbol Description 1 GND Ground 2 ADS Antidistortion 3 VLS Supply 4 INP Input Signal 5 LS1 Output Loudspeaker 1 6 VREF Internal Reference Voltage 7 LS2 Output Loudspeaker 2 8 ADJ Adjust Internal Reference VLS FUNCTIONAL DESCRIPTION TEA7530 performs the following functions: The circuit amplifies the incoming signal and feeds it to the loudspeaker. ♦ The Antidistortion system is incorporated for low current available from line. ♦ The maximum power available on a 50Ω impedance loudspeaker is 25mW at 3V and 100mW at 5V. ELECTRICAL CHARACTERISTICS (Tamb = 25°C, ILS = 30mA unless otherwise specified) Symbol Parameter Test Condition Min. Typ. Max. Unit 2.7 3 3.15 3.3 3.4 V V 5.7 V VLS1 VLS1 Supply ILS = 2mA (fig. 5) ILS = 30mA (fig. 5) VLSM VLS Maximum Ipin8 = 40µA (fig. 5; So = closed) VADJ Voltage Pin 8 ILS = 2 to 30mA (fig. 5 1.0 1.25 1.5 V Loudspeaker Amplifier ILS = 30mA (fig. 6) 30 32 34 dB 2 % 3.5 KΩ 80 mV -20 dB dB G V(5) − V(7) Gain = V(4) THD Distortion f = 300Hz to 2KHz V(5) - V(7) = 0.8Vrms; (fig. 6) ZINPIN Earphone Input (fig. 7) 2.1 VOFFS Output Offset [V(5) - V(7)] (fig. 6) -80 GATT Loudspeaker Attenuated Gain = [V(5) - V(7)] / V(4) V(2) = 0.7V; (fig. 8) V(2) = 0.4V; (fig. 8) 20 2/11 2.8 -30 30 TEA7530 Figure 1: Loudspeaker Gain vs. Voltage on Pin 2 Figure 2: Power Available on Loudspeakervs. VLS Typical Curve. (Voltage Mode Figure 3: Distortion vs. Output Power Figure 4: Output Power vs. Supply Current (Current Mode Supply) 3/11 TEA7530 TEST CIRCUITS Figure 5: Shuntvoltage Regulator / Reference Voltage at Pin 8. Figure 7: Impedance, ZINP 4/11 Figure 6: Loudspeaker Amplifier: Gain/Distortion/Output Offset Figure 8: Anti-loading Feedback System at G = GATT TEA7530 CIRCUIT DESCRIPTION TEA7530 is a 8 pin DIP integrated circuit providing the following facilities: ♦ Loudspeaker amplifier ♦ Antidistortion feed-back system (limited line current compensation) 1.1. LOUDSPEAKER AMPLIFIER The amplifier is divided into 2 main sections. - Automatic Gain Control (AGC) - Push-pull amplifier (bridge structure) a) The AGC section is used for the antidistortion system. ♦When used in a telephone set to avoid larsen effect the AGC automatically decreases loudspeaker amplifier gain. ♦When the required output level exceeds the capabilities of the available current, the AGC decreases the loudspeaker amplifier gain to avoids distortion. b) The output amplifier uses a double push-pull configuration (H bridge) to get maximum dynamic range under limited supply conditions. Figure 9 Figure 10 5/11 TEA7530 Amplifier DC Supply In transmission mode, the supply voltage is controlled by the internal shunt DC regulator. For this reason, the TEA7530 should be supplied from a current source (see: supply considerations). An antidistortion system is embodied which provides AGC control to avoid loudspeaker distortion under current-limited conditions. AGC Circuit action When the supply VLS is insufficient, the voltage at pin 8, falls below the reference voltage 1.2V, resulting in transistor (TR) being switched off, resulting zero current flow in resistor R. This state enables the gain control system. Under these conditions, the shunt DC supply will switch at a rate determined by the time constant of the RC network on pin 2. This switching action accomodates normal speech characteristic under low supply conditions. The AGC will be switched ON when the level on Pin 2 is greater than a reference voltage of 0.4V. Supply Considerations a) Current MODE - Pin 8 is open (VLS = VLS1) or Figure 11 6/11 connected to ground with an external resistor (Rext) higher than 16KΩ. The typical value of VLS is : 40.5KΩ + ( 27KΩ ⁄ ⁄ REXT ) VLS = 1.2V . ( 27KΩ ⁄ ⁄ REXT ) The AGC section is working as described in the previous paragraph. b) Voltage MODE - Pin 8 is shorted or connected to GND with a resistor (R EXT) lower than 16KΩ. In this condition the circuit must be supplied with a DC voltage of 3 to 5.5V. In this case the AGC section is permanently ON. Pin 2 must be shorted to GND (in voltage mode only) to avoid permanent attenuation of the signal at audio input PIN FUNCTIONS PIN 1: GND. PIN 2: AUTOMATIC GAIN CONTROL FILTER The antidistortion system response is adjusted by the R-C network on this pin. The AGC will be switched ON when the level on pin 2 is greater than a reference voltage of 0.4V, the RC-network charges (current source ON) or discharges (current source OFF) according to supply voltage. TEA7530 THEORETICAL VOLTAGE ON PIN 2 Figure 12 - The value of R affects the system time constant and the charge/discharge duty cycle. - The value of C only affects the system time constant. - R should be greater or equal to 150KΩ for correct AGC operation. PIN 3: CIRCUIT SUPPLY VOLTAGE With pin 8 open circuit, VLS is internally stabilized at 3V. When the TEA7530 is under AGC control, the voltage on this pin varies slightly (due to AGC action). PIN 4: EARPHONE INPUT Input for loudspeaker signal Figure 13 Pin 2 7/11 TEA7530 and loudspeaker outputs: 32dB. PIN 5-7: LOUDSPEAKER OUTPUTS Maximum outpt voltage: Vpp = 2VLS - 2.5V (with a gain of 32dB). Maximum output current: depending of the supply current. Figure 14 - ”Asymmetrical” Mode This allows higher voltage operation, but at a lower supply current. Loudspeaker impedance recommended value: 25Ω. Nominal gain available between earphone input and loudspeaker output: 32 - 6 = 26dB. Pin 6: Vref: INTERNAL REFERENCE Output which provides an internally regulated reference voltage. Vref = 1.2V typical MAXIMUM AVAILABLE CURRENT: 5µA Two loudspeaker connection methods are possible, using the amplifier in either symmetrical or asymmetrical mode. Note: It is advisable to connect a 47nF capacitor in parallel with the loudspeaker (between pins 5 and 7). - ”Symmetrical” mode This is for low voltage working, but at a higher supply current. The highest output power is available in this mode, due to the 5.7V maximum supply voltage restriction, imposed by the TEA7530 Loudspeaker impedance recommended value: 50Ω. Nominal gain available between earphone input 8/11 Pin 8: ADJUST VLS This pin is used to adjust the IC supply voltage. Figure 15 TEA7530 MINIDIP PACKAGE MECHANICAL DATA mm DIM Min. A Typ. inch Max. Min. 3.32 Typ. Max. 0.131 a1 0.51 0.020 B 1.15 1.65 0.045 0.065 b 0.356 0.55 0.014 0.022 b1 0.204 0.304 0.008 0.012 D E 10.92 7.95 9.75 0.430 0.313 0.384 e 2.54 0.100 e3 7.62 0.300 e4 7.62 0.300 F 6.6 0260 i 5.08 0.200 L Z 3.18 3.81 1.52 0.125 0.150 0.060 9/11 TEA7530 SO8 PACKAGE MECHANICAL DATA mm DIM Min. Typ. A a1 inch Max. Typ. 1.75 0.1 Max. 0.069 0.25 a2 0.004 0.010 1.65 0.065 a3 0.65 0.85 0.026 0.033 b 0.35 0.48 0.014 0.019 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.020 o 45 (typ.) c1 D 4.8 5.0 0.189 0.197 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F 3.8 4.0 0.150 0.157 L 0.4 1.27 0.016 0.050 M S 10/11 Min. 0.6 0.024 o 8 (max.) TEA7530 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. 1994 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A. 11/11