KA8601C SPEAKER PHONE WITH SPEECH NETWORK INTRODUCTION 48-SDIP-600 The KA8601C is a monolithic integrated circuit for use in high performance speaker phone system. The KA860lC consists of speaker phone and speech network. Speaker phone includes attenuators, amplifiers, level detectors, attenuator control, hybrid amplifiers, regulator and AGC circuit. Speech network includes transmit amp, receive amp, voltage regulator for dialer, side tone control, and line equalizer. FEATURES • Speaker Phone - Low Operating Voltage (3.0 ~ 6.5V) - High Attenuator Gain Range (52dB) - Improved Sensitivity (Four-point Signal Sensing) - Chip Disable for Active or Standby Operation - Microphone Amp Gain set by External Components • Speech Network - Low Operating Voltage (1.5V : speech) - Regulated Voltage for Dialer (Typically 3.3V) - Transmit, Receive, Side Tone Gains set by External Components - Mute Input for DTMF Dialing ORDERING INFORMATION Device Package Operating Temperature KA8601C 48-SDIP-600 - 25°C ~ + 75°C VDD 13 14 MICO TXI sidetone amp POWER 12 GND 23 24 VCC 20 RXI MS 19 RXO- 22 18 NC ZB 17 NC RXOSUM 21 16 REC amp 15 TX amp1 AGC RXO+ mic amp 1.7Vreg RX amp 11 AGC 10 7 VL MICI+ 6 VI MICI- 5 MT 9 4 FO LC 3 FI VR 2 CD SPEECH NET8 WORK PART 1 DTO+ DC level shift FILTER TX amp2 hybrid amp 2 ATTENUATOR CONTROLLER BNM : Back Noise Monitor TXO ATT 3.3Vreg TX Attenuator BNM AGC BNM 25 26 TXI ATT 27 PD TX VB 28 29 DETI TX2 DETO TX2 31 30 DETO RX2 32 mic amp level detector MICI 37 DETI RX2 MICO 38 CT DETI TX1 39 33 DETO TX1 40 34 DETO RX1 41 VC DETI RX1 42 MT PD RX 43 36 GND 44 35 RXI ATT 45 RX Attenuator hybrid amp 1 SPEAKER PHONE PART level detector RXO ATT 46 47 DTI 48 DTO- BLOCK DIAGRAM KA8601C SPEAKER PHONE WITH SPEECH NETWORK PIN CONFIGURATION DTO+ 1 48 DTO- CD 2 47 DTI FI 3 46 RXOATT FO 4 45 RXIATT R4 5 44 GND VI 6 43 PDRX VL 7 42 DETIRX1 LC 8 41 DETORX1 VR 9 40 DETOTX1 MICI- 10 39 DETITX1 MICI+ 11 38 MICO GND 12 37 MICI MICO 13 36 MT TXI 14 35 VC AGC 15 34 CT RXO+ 16 33 DETIRX2 NC 17 32 DETORX2 NC 18 31 DETOTX2 RXO- 19 30 DETITX2 RXI 20 29 PDTX RXOSUM 21 28 VB ZB 22 27 TXIATT MS 23 26 TXOATT VCC 24 25 VDD KA8601C Fig. 2 PIN DESCRIPTION Pin No Symbol Description 1 DTO+ 2 CD 3 FI Filter input. 4 FO Filter output. 5 MT Mute input. A logic “1” sets normal speech mode. 6 VI 7 VL 8 LC Resistor at this pin set the DC characteristics of the circuit. 9 VR A 1.7 volt regulated output which can be used to bias the mic. 10 MICI- Inverting differential input to the mic amp. 11 MICI+ Non-inverting differential input to the mic amp. 12 GND Ground pin for the speech network. 13 MICO Mic amp output. 14 TXI 15 AGC Output of the second hybrid amplifier. Chip Disable. A logic low (<0.8V) sets normal operation. A resistor connected from this pin to VSS sets the AC terminating impedance. Power supply for the speech network. Supply voltage is derived from loop current. T X amp output operates on this pin. Input to the TX amp from the Mic amp. Loop current sensing input. KA8601C SPEAKER PHONE WITH SPEECH NETWORK PIN DESCRIPTION (continued) Pin No Symbol Description 16 RXO+ 17 NC No connection. 18 NC No connection. 19 RXO- 20 RXI 21 RXO SUM 22 ZB Input to the RX current amp. 23 MS Mode select input. A logic “1” → pulse dialing, A logic “0” → tone (DTMF) dialing. 24 VCC A supply voltage pin for the speaker phone part. 25 VDD A regulated 3.3 volt output for an external dialer. 26 TXOATT Output of the TX attenuator. 27 TXIATT Input to the TX attenuator. 28 VB 29 PD TX RX amp non-inverting differential output. RX amp inverting differential output. Input to the RX amp. Summed output of the RX current amp. This voltage is a system AC ground, and biases the volume control. A filter cap is required. An RC at this pin sets the time constant for the TX background monitor. 30 DETITX2 Input to the TX level detector on the mike/speaker side. 31 DETOTX2 Output of the TX level detector on the mike/speaker side. 32 DETORX2 Output of the RX level detector on the mike/speaker side. 33 DETIRX2 Input to the RX level detector on the mike/speaker side. 34 CT 35 VC This pin sets the response time for the circuit to switch modes. Volumn control input. Mute input. A logic low (<0.8V) sets normal operation. A logic high (>2.0V) mutes the 36 MT 37 MICI Input and summing node of the mic amp. 38 MICO Output of the mic amp is set by external resistors. 39 DETTX1 40 DETOTX1 Output of the TX level detector on the line side. 41 DETORX1 Output of the RX level detector on the line side. 42 DETIRX1 Input to the RX level detector on the line side. 43 PD RX A RC at this pin sets the time constant for the RX background monitor. 44 GND Ground pin for the speaker phone part. 45 RXI ATT Input to the RX attenuator and dial tone detector. 46 RXO ATT Output of the RX attenuator. 47 DTI 48 DTO - mic amp. Input to the TX level detector on the line side. Input and summing node of the mic amp. Output of the first hybrid amplifier. KA8601C SPEAKER PHONE WITH SPEECH NETWORK ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Supply Voltage Speaker Phone Value Unit VCC - 1.0 ~ + 7.0 V Voltage at VC VI (VC) - 1.0 ~ VCC + 0.5 V Voltage at CD,MT VI (CM) -1.0 ~ VCC + 1.0 V Voltage at TXI, RXI, HFI VI (TRH) - 0.5 ~ VCC + 0.5 V VCC - 1.0 ~ + 12 V V Supply Voltage Speech Supply Voltage for dialer Network Voltage at MTS, MS Current Through VL, LC VDD - 1.0 ~ + 6.0 VI (MS) - 1.0 ~ VDD + 0.5 V II (VL, LC) 130 mA Current into ZB II (ZB) 3 mA Operating Temperature T OPR - 25 ~ + 75 °C Storage Temperature T STG - 65 ~ + 150 °C ELECTRICAL CHARACTERISTICS Characteristic (Ta = 25°C) Symbol Test Conditions Min Typ Max Unit SPEECH NETWORK (Ta = 25°C, unless otherwise noted) Line Voltage VR Voltage MF Operating Voltage VL VR VDD (MF) Speech Mode IL = 30mA 3.0 3.9 4.7 Pulse Mode IL = 120mA 8 9.8 11.5 Tone Mode IL = 30mA 4.4 5.1 6.5 IL = 30mA Speech Mode 1.55 1.7 1.85 VL = 4.5V Tone Mode 3.0 3.3 3.8 IDD = 1.6mA 3.0 3.3 3.8 Speech Mode 0.5 1.1 2.0 IDD MF (MAX) V V Tone Mode MF Operating Current (Max) V IL = 30mA Pulse Mode 2 2.8 4 Tone Mode 2 2.8 4 mA MICO Bias Voltage VBIAS (MPO) IL = 30mA Speech Mode 0.8 1.08 1.4 V TXI Bias Voltage VBIAS (TxTs) IL = 30mA Speech Mode 0.04 0.086 0.2 V GV (MIC) IL = 30mA Speech Mode 27 30 33 dB 30 64 - dB dB MIC Amp Gain MIC Common Mode Rejection Ratio MIC Gain Reduction T X Gain T X Distortion - CMRR(MIC) ∆GV (MIC) MT = 0V GV (TX) Speech Mode THD TX IL = 30mA -10 -60 - IL = 30mA 30 34.8 60 IL = 80mA 28 31 34 Speech Mode - - 2 IL = 30mA -15 -10.5 -2 IL = 80mA -17 -14 -10 dB % RX Gain GV (RX) Speech Mode RX Distortion THD RX IL = 30mA Speech Mode - - 2 % Side Tone Gain GV (ST) IL = 30mA Speech Mode - 10 15 dB dB KA8601C SPEAKER PHONE WITH SPEECH NETWORK ELECTRICAL CHARACTERISTICS Characteristic Side Tone Rejection MUTE Input Impedance (Continued) Symbol Test Condition Min Typ Max RST 20 25 - dB ZI (MUTE) - 60 - KΩ MUTE Input Low Voltage VIL (MUTE) - 1.0 MUTE Input High Voltage VIH (MUTE) VDD V -0.3 MS Input Low Voltage VIL (MS) MS Input High Voltage VIH (MS) LC Level Shift Unit ∆ VLC 0.8 - - 2.0 IL = 30mA Speech Mode 2.1 2.9 3.5 Pulse Mode 2.1 2.9 3.5 Tone Mode 3.4 4.3 5.2 CD = 0.8V - 5.5 8.0 CD = 2V - 0.6 0.8 V SPEAKER PHONE (Ta = 25°C, VCC = 5.0V, unless otherwise noted) Operating Current Reference Voltage ICC VCC = 6.5V mA 1.8 2.1 2.4 1.5 1.7 1.9 - 1.3 - VC = VB 4.0 6.0 8.0 VCC = 3.5V, VC = VB 4.0 6.0 8.0 VCC = 2.8V, VC = VB - -19 -11 ∆GATT (RX) VCC = 3.5V, to 5.0V -0.5 0 +0.5 ∆GATT AGC (RX) VCC = 2.8V, to 5.0V - -25 -15 dB -22 -20 -17 dB VREF IL = 1.0mA VCC = 3.5V RX Attenuator Gain RX Attenuator Gain Change RX Attenuator AGC Gain Change RX Attenuator Gain (Idle Mode) GATT (RX) GATT RX (IM) RX Attenuator Gain Range GATT (RX) RX Volume Control Range GV CTL (RX) RX DC Output Voltage VC = VB 49 52 54 dB 27 35 - dB VO (RX) - VB - V - ± 10 ±150 mV 3.7 - - V VRXI = 1V - -1.5 -1.0 V - 0.5 3 % RX Mode - +240 - Idle Mode - 0 - T X Mode - -240 - RX to TX Mode RX DC Output High Voltage VOH (RX) VRXI = 3.5V VOL (RX) RX Mode Distortion CT Voltage (with respect to VB) THD RX VCT dB VC = 0.1VB ∆VO (RX) (with respect to VB) dB VC = VB (RX to TX Mode) RX DC Output Voltage Change RX DC Output Low Voltage V Dial Tone Detector Threshold VTH (DET) 10 15 20 mV T X Attenuator Gain GATT (TX) 4.0 6.0 8.0 dB T X Attenuator Gain Range GATT (TX) 49 52 54 dB VO (TX) - VB - V ∆VO (TX) - ± 30 ±150 mV T X Output DC Voltage T X Output DC Voltage Change VC = VB, VRXI = 3.0V mV KA8601C SPEAKER PHONE WITH SPEECH NETWORK ELECTRICAL CHARACTERISTICS Characteristic (Continued) Symbol Test Conditions Min Typ Max Unit T X Output High Voltage VOH (TX) VTXI = 3.5V 3.7 - - V T X Output Low Voltage VOL (TX) VTXI = 1.0V - 0.5 1 V T X Mode Distortion THDTX - 0.8 3 % MIC Voltage Gain GV (MIC) 70 80 - dB MIC Output Offset Voltage VOO (MIC) -50 0 +50 mV MIC Output High Voltage VOH (MIC) VMIC = 1.0V 3.7 - - V MIC Output Low Voltage VOL (MIC) VMIC = 3.0V - - 200 mV MIC Input Bias Current IBIAS (MIC) - -40 - nA Muting (Gain) GV (MUTE) -55 - - dB MIC Amp Distortion THD MIC - 0.15 - % MUTE Input High Voltage VIH (MUTE) 2.0 - VCC V MUTE Input Low Voltage VIL (MUTE) 0 - 0.8 V GV (HA) 60 80 - dB DTO-Output High Voltage VOH (DTO -) 3.7 - - V DTO-Output Low Voltage VOL (DTO -) - - 250 mV DTO+Output High Voltage VOH (DTO +) IO = -5mA 3.7 - - V DTO+Output Low Voltage VOL (DTO +) IO = 5mA - - 250 mV DTO Distortion THD DTO IO = -5mA - 0.3 - % VIO (F) IO = 5mA -22 -90 0 mV 0 -50 - mA Open Loop Gain (Hybrid Amp) Filter Offset Voltage Filter Input Bias Current VBIAS (F) VMT = 2V, f = 1KHz 0.3KHz ≤ f ≤ 10KHz KA8601C SPEAKER PHONE WITH SPEECH NETWORK APPLICATION INFORMATION FUNCTION DESCRIPTION SPEECH NETWORK 1. MICROPHONE AMPLIFIER This microphone amplifier is equipped with a fixed gain (30dB). Its basic configuration is shown in figure 3. MICI+ + 30dB MICO - MIC20K 20K MT Fig .3 This amplifier has a mute function. If a mute signal from the dialer is inputted when the speech network is in the mute mode, the microphone amplifier will be muted. 2. VOLTAGE REGULATOR (DIALER INTERFERENCE) This voltage regulator has a minimum output voltage of 3.1 volts. When the dialer is not in motion, its minimum current is 1.0mA, where as when the dialer is moving the minimum current is 2.2mA. 3. VOLTAGE REFERENCE Generally when in the voltage reference mode, the microphone's bias voltage is used, but when in the TXlATT mode, DC bias voltage is used. The output voltage of the voltage reference is a minimum of 1.6 volts. SPEAKER PHONE 1. MICROPHONE AMPLIFIER This device amplifies outside microphone signals, which are inputted while in the inverting mode. As it alters elements, the microphone amplifier allows for them to be modulated. Its open loop gain is 80dB, while the band width is typically 1.0KHz. It has a mute function, and when operating in the mute mode at least 2.0V, the microphone amplifier gain is reduced to around 40dB. If the mute mode is not used, it must connected with the ground. Rf MIC Ri MICO + MT Bias Voltage Fig. 4 KA8601C 2. SPEAKER PHONE WITH SPEECH NETWORK VOLUME CONTROL The volume control can only be applied in the receive mode. If the voltage of the VC mode is the same as the VB, the receive attenuator gain is maximized and the transmit gain is minimized. At the same time, if the VC mode voltage is less than the VB, the receive attenuator gain is reduced. VB VC KA8601C VOLUME Fig. 5 3. VOICE DETECTION FUNCTION The voice detection function compares the microphone amplifier output level with the outside audio amplifier level and the transmit attenuator output level with the receive attenuator input level, after which they are inputted into the control box. The block diagram of the voice detection function is as follows: DETO RX 1 DETIRX 1 PDTX PDRX DETO TX 1 Background Noise Monitor A1 A3 DETI TX 1 Log Amp Log Amp Comparator Comparator C1 C2 CO1 CO2 CO3 CO4 Log Amp Log Amp DETITX 1 Attenuator Control Box A2 A4 DETI RX 1 DETO TX 1 DETO TX 1 Fig. 6 It is useful to use a background noise monitor when high background noise occurs. When the input signals to the background noise monitor are increased, voltage for the PDRX (PDTX) mode is stably increased. The increase time is determined by 100KΩ and 47µF. 4. ATTENUATOR CONTROL BOX In figure 6, each signal coming into the log amplifier is amplified and then inputted into the comparator (C1, C2). The comparator compares the amplified signal levels, after which they are inputted into the attenuator control box. The attenuator control box processes these signals (CO1, CO2, CO3, CO4) as logic signals, and which are put into one of the following modes: KA8601C SPEAKER PHONE WITH SPEECH NETWORK 1. Receive Mode 2. Transmit Mode 3. Slow Idle Mode 4. Fast Idle Mode Which of the above modes is to be determined depending on the following conditions: 1) Receive Mode DETOTX1 < DETORX1, DETOTX2 < DETORX2, PDTX, X, PDRX : 1 2) Transmit Mode DETOTX1 > DETORX1, DETOTX2 > DETORX2, PDTX : 1, PDRX : X 3) Slow Idle Mode DETOTX1 > DETORX1, DETOTX2 > DETORX2, PDTX : 0, PDRX : X DETOTX1 < DETORX1, DETOTX2 < DETORX2, PDTX : 0, PDRX : X DETOTX1 < DETORX1, DETOTX2 > DETORX2, PDTX : 0, PDRX : X DETOTX1 > DETORX1, DETOTX2 < DETORX2, PDTX : 0, PDRX : X 4) Fast Idle Mode DETOTX1 > DETORX1, DETOTX2 < DETORX2, PDTX : 0, PDRX : 0 DETOTX1 < DETORX1, DETOTX2 > DETORX2, PDTX : Y, PDRX : Y * "<" and ">" refer to voltage level : "X" refers to "It doesn't matter : "Y" is not zero 5. SWITCHING TIME The switching time of the speaker phone is determined by the CT and RT of the outside elements. 1. Idle Mode → RX or TX Mode ST = 4,000 X CT 2. TX or RX Mode → Fast Idle Mode ST = 2,000 X CT 3. TX or RX Mode → Slow Idle Mode ST = RT X CT * CT, RT refer to the capacitor and resistor between Pin 34 and VCC. KA8601C APPLICATION CIRCUIT SPEAKER PHONE WITH SPEECH NETWORK