AN6425K Speech Network Circuit ■ Overview • Speech network IC for the multifunctional telephone sets • Capable of interfacing with the light-weight small receivers and ECM transmitters • Built-in 2V REG constant voltage source (2V typ) for ECM • Built-in non-linear circuits in the transmitter and receiver 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1.778 26.7±0.3 ■ Features 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0.5±0.1 0.9±0.25 Unit : mm The AN6425K is a high-function speech network IC with speaker amplifier. It incorporates a transmitter-system non-linear circuit, receiver digital VRs, etc. and is suitable for realizing the multifunctional telephone sets. 1.05±0.25 systems in order to eliminate ambient noises 8.4±0.3 • Built-in speaker amplifier and capable of driving with a main 4.8±0.25 3.05±0.25 wire current • Built-in hold-tone amplifier, key-in-tone amplifier, and + 0.1 5 – 0.0 DTMF transmitter, and capable of setting the mode with the control pins • Automatic gain control (automatic pad function) according to a circuit curret • Built-in tertiary active filter circuit and capable of sending a DTMF circuit with much higher harmonic at a low distortion factor • Built-in single touch receiver volume-up function (about 6dB) 0.3 3 to 15˚ 10.16±0.25 28-pin Shrunk DIL Plastic Package (SDIP028-P-0400B) ■ Block Diagram VL 28 27 26 25 24 23 22 21 20 19 18 17 16 15 80kΩ CLASS B BTL – + + SP Amp. REC in D6dB – – CLASS A Push pull D5dB D3dB + REC DRIVER REC DRIVER DVR 30kΩ 1V 2kΩ 4kΩ 40kΩ 30kΩ 2kΩ KT 2V REG HT 2V 1V REFF TT in VL 1V D12 dB SEND Amp Battery Selector D3dB 1 2 3 4 5 MIC in Logic INV NAND MUTE 65kΩ GND Filter Amp. 6 7 8 9 10 11 12 13 14 ■ Absolute Maximum Ratings (Ta=25˚C) Parameter Symbol Rating 14.4 * Unit 120 * 1200 * mA Supply voltage VL Supply current IL Power dissipation PD Operating ambient temperature Topr –20 to + 65 ˚C Storage temperature Tstg –55 to +150 ˚C V mW * VCC × ICC <1200mW ■ Recommended Operating Range (Ta=25˚C) Parameter Symbol Range VL 3 to 12V Operating supply voltage range ■ Electrical Characteristics (Ta=25˚C) Parameter Symbol Condition Receiver gain GV (REC) Open between the Pins19 and 20. Measure the output between the Pins22 and 23 when a signal (–55dBm) is input to the Pin18. Receiver distortion factor THD (REC) Open between the Pins19 and 20. Measure the output distortion factor between the Pins 22 and 23 when a signal (–55dBm) is input to the Pin18. Receiver maximum output voltage VO (REC) D Automatic pad AP (REC) D Receiver noise prevention MUTE (REC) Receiver D digital VR DVR Receiver noise output Vno (REC) Transmitter gain GV (SEND) Transmitter distortion factor THD (SEND) Transmitter maximum transmission level VO (SEND) Transmitter D automatic pad AP (SEND) Transmitter noise prevention Vno (SEND) HOLD TONE gain GV (HOLD) TOUCH TONE gain GV (TOUCH) TOUCH TONE distortion factor THD (TOUCH) * IL=30mA and Freq=1kHz unless otherwise specified. Input a signal to the Pin18 and measure the output between the Pins22 and 23 at an output distortion factor of 5%. Input a signal (–45dBm) to the Pin18 and measure an output change between the Pins22 and 23 when IL changes from 80mA to 30mA. Input a signal (–45dBm) to the Pin18 and measure an output change between the Pins 22 and 23 when the Pin12 changes from no microphone input signal to –40dBm. Input a signal (–45dBm) to the Pin18 and measure an output change between the Pins 22 and 23 when the Pin12 is set from H to L. Measure the output between the Pins22 and 23 when there is no signal at the Pin18. Open bitween the Pins3 and 6. Measure the output between the Pins28 and 1 when a signal (–45dBm) is input to the Pin12. min 48 max Unit 50.5 53 dB 1 5 % 0 +3 –6 –3 –1.5 dB –7 –5 –3 dB 4 6 8 dB –50 –45 dBm 42.5 45 dB 1.5 5 % 40 Open between the Pins3 and 6. Measure the output distortion factor between the Pins28 and 1 when a signal (–45dBm) is input to the Pin12. Input a signal to the Pin12 and measure the output between the Pins28 and 1 at an output distortion factor of 5%. Input a signal (–35dBm) to the Pin12 and measure an output change between the Pins 28 and 1 when IL changes from 80mA. Measure the output between the Pins28 and 1 when there is no signal at the Pin18. Ground the Pin24. Input a signal (–30dBm) to the Pin17 and measure the output change between the Pins 28 and 1. Ground a signal (–45dBm) to the Pin16 and measure the output between the Pins28 and 1. Ground the Pin14. Input a signal (–45dBm) to the Pin16 and measure the output distortion factor between the Pins 28 and 1. typ dBm 2 5 –6 –3 –1.5 dB –65 –60 dBm 23.5 26.5 29.5 dB 39 41.5 44 dB 1 3 % dBm ■ Electrical Characteristics (cont.) (Ta=25˚C) Parameter Symbol AP (TOUCH) TOUCH TONE D automatic pad SP amplifier gain GV (SP) SP distortion factor THD (SP) Condition min Ground the Pin14. Input a signal (–45 dBm) to the Pin16 and measure an output change between the Pins 28 and 1 when IL changes from 80mA to 30mA. Ground the Pin15. Input a signal (–50dBm) to the Pin24 and measure the output between the Pins 25 and 26. Ground the Pin15. Input a signal (–50dBm) to the Pin24 and measure the output distortion factor between the Pins 25 and 26. typ –6 –3 45 50 max Unit –1.5 dB dB 10 % * IL=30mA and Freq=1kHz unless otherwise specified. ■ Pin Descriptions Pin No. 1 2 3 4 Pin name GND 2V REG 1V REF BT Typical waveform Description DC 0V Ground pin. Connect to the output of the diode bridge. DC 2V 2V internal stabillized power supply output pin. Connect to GND via 220µF. The current obtainable from this pin is 5mA or less (at IL=20mA). DC 1V 1V reference coltage output pin. Connect to GND via 47µF. No current is allowed to be input/output from this pin. DC 0 to 6V (Supplied from Outside) Equivalent circuit 2V REG 2 VCC – + 3 10kΩ 1V External battery connection pin. Connect the 3 to 6V battery to GND. Connect to GND directly when the BT function is not used. Vref VL 65.3kΩ 5 SEND OUTPUT 0.3V 6 SEND DRIVER Vref Transmitter output. Transmitter gain control pin. Controls the gain and frequency characteristic of the transmitter system with external C and R. 5 VCC 6 VL 7 1/2VL DC 5/7 × VL Automatic pad control pin. Capable of controlling the pad operating point with the external resistor. 20kΩ 7 47kΩ ■ Pin Descriptions (cont.) Pin No. 8 Pin name Mute Typical waveform W/o External Capafitor Description Equivalent circuit VCC VCC Noise precentice peak hold pin. Connect to GND via 10µF. 8 DC W/External Capafitor VCC 10 11 – + 9 9 LPF (1) Transmitter filter pin. Constitutes the tertiary active filter with the external parts C and R, and capable of controlling the high-pass transmitter frequency characteristic. LPF (2) LPF (3) VCC 40kΩ 10 + – VCC 11 VCC 12 MIC input 1V Microphone input pin. Input pin for the microphone. VCC 10kΩ 12 VCC VCC 13 HC 0V HOLD TONE control pin. The HOLD TONE transmission mode is set by setting this pin to Low. 10kΩ 13 Hole Tone Mode VCC VCC 14 DMC 0V DIAL MUTE control pin. The DTMF transmission mode is set by setting this pin to Low. 10kΩ 14 DTMF Transmission Mode VCC VCC 15 SPC 0V SPEAKER control pin. The speaker mode is set by setting this pin to Low. 10kΩ 15 Speaker Mode VCC 16 TT input 1V DTMT signal input pin. Inputs a DTMF signal. A signal is sent to the circuit when the Pin14 is at Low. Vref 10kΩ 16 ■ Pin Descriptions (cont.) Pin No. Pin name Typical waveform Description Equivalent circuit VCC KT/HT 30kΩ 1V KT/HT input 17 DVR input 0V KT/HT signal input pin, Digital VR ON Pin. Inputs a KEY IN TONE or HOLD TONE signal. If the Pin14 is set to Low, the KT signal is output to the receiver, and if the Pin13 is set to Low, the HT signal is output to the curcuit and speaker. The receiver gain is improved 6dB by setting this pin to Low instantaneously. 45kΩ Vref VCC + – 16 4kΩ Digital VR ON VCC 18 REC input 1V Receiver signal input pin. Inputs a receiver signal from the side tone preventive circuit network. Vref 18 VCC 19 20 REC NFB REC output 1V 1V 19 VCC 82kΩ 10kΩ Receiver gain control pin, Receiver signal output pin. Capable of controlling the frequency characteristic and gain of the receiver system with the external parts C and F of the Pins19 and 20. The receiver signal/HOLD TONE signal/KEY IN TONE signal is output to the Pin20 by the HC/DMC/SPC control. 10kΩ VCC – 20 + VCC VCC VCC 21 Driver input 22 Driver output (1) 23 Driver output (2) 1V 1V Receiver amplifier signal input pin, Receiver output (1) pin, Receiver output (2) pin. Inputs a receiver signal from the Pin20 to the Pin21. BTL output at the Pins20 and 23. 21 + 22 1V – 2kΩ 2kΩ Vref VCC Vref 2kΩ + 23 – 2kΩ VCC 24 SP input 1V Speaker amplifier signal input pin. Inputs a receiver signal from the Pin20. Vref 10kΩ 24 ■ Pin Descriptions (cont.) Pin No. Pin name Typical waveform Description Equivalent circuit 25 25 26 SP out (1) SP out (2) 1V 1V Speaker output (1) pin, Speaker output (1) pin. Output of the class-A differential amplifier and connected to the speaker through the transformer (300Ω) with intermediate tap. 26 VL 27 28 DC 1 to 8V BS VL 3 to 10V Power supply boot strap pin. Connects to the Pin28 via 47µF. The DC resistance of the communication circuit is determined by connecting an external resistor to GND. 2kΩ 50Ω 27 Supply current input pin. Connects to the + output of the diode bridge. ■ Supplementary Descriptions • Electrical Characteristics Design Reference Values (Ta=25˚C) Parameter Symbol KEY IN TONE gain GV (KEY) ∆ Transmitter noise preventive attenuation MUTE (SEND) MUTE (MIC) RL (REC) ∆ Transmitter noise preventive selector level Low impedance drive Condition Measure the output between the Pin22 and 23 when key input (Pin17)=–40dBm. To the Pin8 – GND REC output ∆ –1dB R (REC)=130Ω, Input=–50dBm min typ max Unit 40 dB –14 dB –62 dBm 35 dB DC resistance (1) RDC (1) With IL=20mA, measure the DC voltage at the Pin28 when connecting 6.2kΩ between the Pins27 and 1. 3.8 V DC resistance (2) RDC (2) With IL=100mA, measure the DC voltage at the Pin28 when connecting 6.2kΩ between the Pins27 and 1. 10 V 2 kΩ 1.5 kΩ 2 V 1 V AC impedance (1) ZAC (1) AC impedance (2) ZAC (2) Internal regulator voltage VREG Internal reference voltage VREF Measure the AC impedance between the Pins28 and 1 at IL=20mA. Measure the AC impedance between the Pins28 and 1 at IL=100mA. Measure the DC voltage at the Pin2 at IL=30mA. Measure the DC voltage at the Pin3 at IL=20mA. Note) The above characteristics are design reference values and not guaranteed values. ■ Characteristics Curve Characterristic Impedance 28 33µF REC IN=–55dBm IC 33µF AC Impedance ZAC (kΩ) Circuit Voltage VL (V) 10 8 VL 6 4 LF Imoedance Analyzer (f=1kHz) 3 2 28 820Ω 1 + 27 33µF 2 6.2kΩ 0 0 20 40 60 80 100 0 120 Receiver Automatic Pad Characteristics –2 0 20 40 60 80 100 Circuit Current IL (mA) Receiver Mute Microphone Automatic Pad Characteristics 0 –2 Vout (REC) –4 –6 –4 6 22kΩ –6 Vout (MIC) –8 –10 –12 –14 –80 –70 –60 –50 –40 –18 –30 20 0 Microphone Input Vin (MIC) (dBm) 60 80 100 TT I/O Characteristics Circuit Output Vout (MIC) (dBm) Vout (TT) 0 –2 –4 –6 –8 0 20 40 60 80 100 Circuit Current IL (mA) 120 6 10 3 –10 6 3 22kΩ –20 –30 –40 –50 –70 –60 –50 –40 –30 Open 6 3 –10 Vout (MIC) 6 –20 3 22kΩ 28 –30 820Ω + 33µF –40 –50 –70 –60 –50 –40 –30 +10 –20 IL=30mA fin=1khz 0 –10 Vout (SP) 10 –20 8 –30 6 4 –40 THD (SP) 2 –50 IL=30mA fin=1kHz –60 –80 120 Speaker I/O Characteristics Closed Circuit Characteristics 0 100 IL=30mA fin=1kHz 0 Open 2 80 +10 +20 3 22kΩ TT Input=–40dBm 60 Microphone Input Vin (MIC) (dBm) Speaker Output Vout (SP) (dBm) 6 4 40 Transmitter I/O Characteristics –60 –80 120 20 6 –10 40 Circuit Current IL (mA) TT (DTMF) Automatic Pad Characteristics Circuit Output Vout (TT) (dBm) 3 –16 –8 –90 20 +20 Circuit Output Vout (MIC) (dBm) 0.001µF 0 Mic. Input=–40dBm Circuit Output Vout (TT) (dBm) Receiver Output Vout (REC) (dB) 3 –8 Circuit Current IL (mA) –2 6 Vout (REC) –6 –10 120 Circuit Current IL (mA) REC IN=Constant 22kΩ –4 –20 Touch Tone Input Vin (TT) (dBm) –60 –80 –70 –60 –50 –40 –30 SP Input Vin (SP) (dBm) 0 –20 Total Harmonic Distortion THD (SP) (%) 4 Receiver Output Vout (REC) (dBm) VL– IL 12 L2 L1 6.8kΩ SP 8Ω + 8.2kΩ + + 2.7kΩ 68kΩ + + 4.7kΩ 47µF/ 16V 47µF/16V 47µF/ 16V 0.022µF Balancing Network 2.2µF/ 50V + SP AGC circuit SP Stablized Power Supply 10µF/16V 10µF/16V 47µF/16V 100kΩ 0.01µF + 1kΩ 12kΩ 330Ω 1 28 47µF/16V + 33kΩ 470µF/6.3V + 2 27 33kΩ 6 5 4 3 + 23 24 25 47µF/16V 2.2kΩ 0.01µF 1kΩ VR1 0.01µF 1kΩ 10kΩ + 7 AN6425K 22 3.3kΩ 1kΩ 0.22µF + 8 0.001µF 21 0.01µF 6.8kΩ 9 11 18 2.2kΩ 10 19 47kΩ 20 2.2kΩ 0.0047µF 0.15 µF 2.2kΩ Piezo-electric Receiver 26 + 0.022µF 1.8kΩ 3V 6.2kΩ 47µF/16V 33Ω 0.068µF 0.47µF 10µF/16V 10µF/16V 0.0015µF 0.033µF 0.068µF 0.22µF 12 17 10kΩ 0.033µF 0.1µF 0.0082µF 14 13 HC 15 16 10kΩ 0.0022µF 100kB SPC DMC MF 0.01µF ECM ■ Application Circuit