BL34118 Voice Switched Speakerphone Circuit BL34118 The BL34118 Voice Switched Speakerphone Circuit incorporates the necessary amplifiers, attenuators, level detectors, and control algorithm to form the heart of a high quality hands-free speakerphone system. Included are a microphone amplifier with adjustable gain and MUTE control, Transmit and Receive attenuators which operate in a complementary manner, level detectors at both input and output of both attenuators, and background noise monitors for both the transmit and receive channels. A Dial Tone Detector prevents the dial tone from being attenuated by the Receive background noise monitor circuit. Also included are two line driver amplifiers, which can be used to form a hybrid network in conjunction with an external coupling transformer. A high-pass filter can be used to filter out 60Hz noise in the receive channel, or for other functions. A chip Disable pin permits powering down the entire circuit to conserve power on long loops where loop current is at a minimum. The BL34118 may be operated from a power supply, or it can be powered from the telephone line, requiring typically 5.0 mA. The BL34118 can be interfaced directly to Tip and Ring (through a coupling transformer) for stand-alone operation, or it can be used in conjunction with a handset speech network and/or other features of a feature phone. Improved Attenuator Gain Range: 52 dB Between Transmit and Receive Low Voltage Operation for Line-Powered Applications (3.0 – 6.5V) 4-Point Signal Sensing for Improved Sensitivity Background Noise Monitors for Both Transmit and Receive Paths Microphone Amplifier Gain Set by External Resistors – Mute Function Included Chip Disable for Active/Standby Operation On Board Filter Pinned-Out for User Defined Function Dial Tone Detector to Inhibit Receive Idle Mode During Dial Tone Presence Standard 28-Pin Plastic DIP Package and SOIC Package Available Compatible with BL34119 Speaker Amplifier PIN CONNECTIONS( Top View ) FO 1 28 GND FI 2 27 CPR CD 3 26 RLI1 Vcc 4 25 RLO1 HTO+ 5 24 TLO1 HTO- 6 23 TLI1 HTI 7 22 RXO TXO 8 21 RXI TXI 9 20 RLI2 MCO 10 19 RLO2 MCI 11 18 TLO2 MUT 12 17 TLI2 VLC 13 16 CPT CT 14 15 VB http://www.belling.com.cn -1- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 PIN DESCRPTION Pin Name Description 1 FO Filter output. Output impedance is less than 50 ohms. 2 FI Filter input. Input impedance is greater than 1.0 Mohm. 3 CD Chip Disable. A logic low (<0.8V) sets normal operation. A logic high (>2.0V) disables the IC to conserve power. Input impedance is nominally 90 kΩ. 4 VCC A supply voltage of +2.8 to +6.5 volts is required, at AGC circuit reduces the receive attenuator gain by 5 HTO+ ≈ 5.0 mA. As Vcc falls from 3.5 to 2.8 volts, an ≈ 25 db (when in the receive mode). Output of the second hybrid amplifier. The gain is internally set at –1.0 to provide a differential output, in conjunction with HTO-, to the hybrid transformer. 6 HTO- Output of the first hybrid amplifier. The gain of the amp is set by external resistors. 7 HTI Input and summing node for the first hybrid amplifier. DC level is 8 TXO Output of the transmit attenuator. DC level is approximately VB. 9 TXI Input to the transmit attenuator. Max. signal level is 350 mVrms. Input impedance is 10 MCO Output of the microphone amplifier. The gain of the amplifier is set by external resistors. 11 MCI Input and summing node of the microphone amplifier. DC level is 12 MUT Mute input. A logic low (<0.8V) sets normal operation. A logic high (>2.0V) mutes the microphone ≈ VB. ≈ ≈ 10 kΩ. VB. amplifier without affecting the rest of the circuit. Input impedance is nominally 90 kΩ. 13 VLC Volume control input. When VLC = VB, the receive attenuator is at maximum gain when in the receive mode. When VLC = 0.3VB, the receive gain is down 35 dB. Does not affect the transmit mode. 14 CT An RC at this pin sets the response time for the circuit to switch modes. 15 VB An output voltage ≈ Vcc/2. This voltage is a system as ground, and biases the volume control. A filter cap is required. 16 CPT An RC at this pin sets the time constant for the transmit background monitor. 17 TLI2 Input to the transmit level detector on the mike/speaker side. 18 TLO2 Output of the transmit level detector on the mike/speaker side, and input to the transmit background monitor. 19 RLO2 Output of the receive level detector on the mike/speaker side. 20 RLI2 Input to the receive level detector on the mike/speaker side. 21 RXI Input to the receive attenuator and dial tone detector. Max input level is 350 mVrms. Input impedance is ≈ 10 kΩ. 22 RXO Output of the receive attenuator. DC level is approximately VB. 23 TLI1 Input to the transmit level detector on the line side. 24 TLO1 Output of the transmit level detector on the line side. 25 RLO1 Output of the receive level detector on the line side, and input to the receive background monitor. 26 RLI1 Input to the receive level detector on the line side. 27 CPR An RC at this pin sets the time constant for the receive background monitor. 28 GND Ground pin for the entire IC. http://www.belling.com.cn -2- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 BLOCK DIAGRAM Microphone Tip ZB Tx Attenuator Mute AGC Background Noise Monitor -1.0 Level Detectors Ring Attenuator Control Background Noise Monitor Level Detectors Vcc Bias Chip Disable Speaker Dial Tone Detector Rx Attenuator Filter Power Amplifier Volume Control ABSOLUTE MAXIMUM RATINGS Parameter Value Units -1.0, +7.0 Vdc Voltage at CD (Pin 3), MUT (Pin 12) -1.0, Vcc + 1.0 Vdc Voltage at VLC (Pin 13) -1.0, Vcc + 0.5 Vdc Voltage at TXI (Pin 9), RXI (Pin21), FI (Pin 2) -0.5, Vcc + 0.5 Vdc -65 to +150 ºC Supply Voltage (Pin 4) Storage Temperature Range RECOMMENDED OPERATING LIMITS Parameter Min Max Units 3.5 - 6.5 Vdc CD Input (Pin 3), MUT Input (Pin 12) 0 - Vcc Vdc IVB (Pin 13) - - 500 µA 0.3xVB - VB Vdc Attenuator Input Signal Voltage (Pins 9, 21) 0 - 350 mVrms Microphone Amplifier, Hybrid Amplifier Gain 0 - 40 dB Load Current @ RXO, TXO (Pins 8, 22) Supply Voltage (Pin 4) VLC ( Pin 13) Typ 0 - @ MCO (Pin 10) 0 - @ HTO-, HTO+ (Pins 6, 5) 0 - ± 2.0 ± 1.0 ± 5.0 -20 - +60 Ambient Operating Temperature Range http://www.belling.com.cn -3- Total 11 Pages mA °C 8/15/2006 Wrote by 2006 BL34118 ELECTRICAL CHARACTERISTICS (TA=+25°C, Vcc=5.0V, CD ≤ 0.8V, unless noted) Parameter Symbol Min Typ Max Units - 5.5 8.0 mA - 600 800 µA RCD 50 90 - kΩ CD Input Voltage – High VCDH 2.0 - Vcc Vdc _ Low VCDL 0 - 0.8 Vdc VB - 1. 3 - Vdc 1.8 2.1 2.4 Power Supply Vcc Supply Current (Vcc=6.5V, CD=0.8V) Icc (Vcc=6.5V,CD= 2.0V) CD Input Resistance (Vcc=VCD=6.5V) VB Output Voltage (Vcc = 3.5V) (Vcc = 5.0V) VB Output Resistance (IVB = 1.0 mA) ROVB - 400 - Ω VB Power Supply Rejection Ratio (CVB = 220 uF, f = 1.0kHz) PSRR - 54 - dB ATTENUATORS (TA = +25°C) Receive Attenuator Gain (f = 1.0 kHz, VLC = VB) dB Rx Mode, RXI = 150 mVrms (Vcc = 5.0V) GRX +4.0 +6.0 +8.0 Rx Mode, RXI = 150 mVrms (Vcc = 3.5V) GRX +4.0 +6.0 +8.0 Gain Change – Vcc = 3.5V versus Vcc = 5.0V ∆GRX1 -0.5 0 +0.5 AGC Gain Change – Vcc = 2.8V versus Vcc = 5.0V ∆GRX2 - -25 -15 GRXI -22 -20 -17 ∆GRX3 49 52 54 VCR 27 35 - dB VRXO - VB - Vdc ∆RXO DC Voltage (Rx to Tx Mode) ∆VRXO - ± 10 ± 150 mV RXO High Voltage (Iout = - 1.0mA RXI = VB + 1.5V) VRXOH 3.7 - - Vdc RXO Low Voltage ( Iout = - 1.0 mA, RXI = VB – 1.0, Output VRXOL - -1.5 -1.0 Vdc RRXI 7.0 10 14 kΩ Idle Mode, RXI = 150 mVrms Range (Rx to Tx mode) Volume Control Range (Rx Mode, 0.3VB < VLC < VB) RXO DC Voltage (Rx Mode) measured with respect to VB) RXI Input Resistance (RXI < 350 mVrms) Transmit Attenuator Gain (f = 1.0 kHz) dB Tx Mode, TXI = 150 mVrms GTX +4.0 +6.0 +8.0 Idle Mode, TXI = 150 mVrms GTXI -22 -20 -17 Range (Tx to Rx Mode) ∆GTXI 49 52 54 TXO DC Voltage (Tx Mode) VTXO - VB - Vdc ∆TXO DC Voltage (Tx to Rx Mode) ∆VTXO - ± 30 ± 150 mV TXO High Voltage (Iout = -1.0 mA TXI = VB +1.5V) VTXOH 3.7 - - Vdc TXO Low Voltage (Iout = +1.0 mA, TXI = VB – 1.0V, Output VTXOL - -1.5 -1.0 Vdc TXI Input Resistance (TXI < 350 mVrms) RTXI 7.0 10 14 kΩ Gain Tracking ( GRX + GTX, @ Tx, Idle, Rx) GTR - ± 0.1 - dB measured with respect to VB) http://www.belling.com.cn -4- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 ATTENUATOR CONTROL (TA = +25°C) CT Voltage ( Pin 14 – VB) VCT mV Rx Mode (VLC = VB) - +240 - Idle Mode - 0 - Tx Mode - -240 - CT Source Current (switching to Rx mode) ICTR -85 -60 -40 µA CT Sink Current (switching to Tx mode) ICTT +40 +60 +85 µA CT Slow Idle Current ICTS - 0 - µA CT Fast Idle Internal Resistance RFI 1.5 2.0 3.6 kΩ VLC Input Current IVLC - -60 - nA Dial Tone Detector Threshold VDT 10 15 20 mV MICROPHONE AMPLIFIER (TA = +25°C, VMUT ≤ 0.8V, AVCL = 31 dB unless otherwise noted) MCOVOS -50 0 +50 mVdc Open Loop Gain (f < 100 Hz) AVOLM 70 80 - dB Gain Bandwidth GBW M - 1.0 - MHz Output High Voltage (Iout = -1.0mA, Vcc = 5.0V) VMCOH 3.7 - - Vdc Output Low Voltage (Iout = +1.0mA) VMCOL - - 200 mVdc Input Bias Current (@ MCI) IBM - -40 - nA Muting (∆Gain) (f = 1.0KHz, VMUT = 2.0 V) GMT -55 - - dB - -68 - Output Offset (VMCO – VB, Feedback R = 180 kΩ) (300 Hz < f < 10 kHz) MUT Input Resistance ( Vcc = VMUT = 6.5V) RMUT 50 90 - kΩ MUT Input – High VMUTH 2.0 - Vcc Vdc MUT Input – Low VMUTL 0 - 0.8 Vdc Distortion ( 300 Hz < f < 10 kHz) THDM - 0.15 - % HVOS -20 0 +20 mVdc HTO- to HTO+ Offset (Feedback R = 51 kΩ) HBVOS -30 0 +30 mVdc Open Loop Gain ( HTI to HTO-, f < 100 Hz) AVOLH 60 80 - dB Gain Bandwidth GBW H - 1.0 - MHz Closed Loop Gain ( HTO- to HTO+) AVCLH -0.35 0 +0.35 dB IBH - -30 - nA HTO- High Voltage ( Iout = -5.0 mA) VHT-H 3.7 - - Vdc HTO- Low Voltage ( Iout = +5.0 mA) VHT-L - - 250 mVdc HTO+ High Voltage ( Iout = -5.0 mA) VHT+H 3.7 - - Vdc HTO+ Low Voltage ( Iout = +5.0 mA) VTH+L - - 450 mVdc Distortion ( 300 Hz < f < 10 kHz, See Figure 1) THDH - 0.3 - % HYBRID AMPLIFIER (TA = +25°C) HTO- Offset (VHTO- - VB, Feedback R = 51 kΩ) Input Bias Current ( @ HTI) http://www.belling.com.cn -5- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 LEVEL DETECTORS AND BACKGROUND NOISE MONITORS (TA = +25°C) Transmit-Receive Switching Threshold ITH 0.8 1.0 1.2 Source Current at RLO1, RLO2, TLO1, TLO2 ILSO - -2.0 - mA Sink Current at RLO1, RLO2, TLO1, TLO2 ILSK - 4.0 - µA CPR, CPT Output Resistance ( Iout = 1.5 mA) RCP - 35 - Ω ICPLK - -0.2 - µA FOVOS -200 -90 0 mV FO Sink Current IFO 150 260 400 µA FI Bias Current IFI - -50 - nA Rx Mode ( From FI to RXO, FO connected to RXI) THDR - 0.5 3.0 % Tx Mode ( From MCI to HTO-/HTO+, includes Tx attenuator) THDT - 0.8 3.0 % ( Ratio of Current at RLI1 + RLI2 to 20 uA at TLI1 + TLI2 to switch from Tx to Rx) CPR, CPT Leakage Current FILTER (TA = +25°C) Voltage Offset at FO (VFO – VB, 220 kΩ from VB to FI) SYSTEM DISTORTION (TA = +25°C) 1. All currents into a devices pin are positive, those out of a pin are negative, Algebraic convention rather than magnitude is used to define limits. 51 K HTOVin 0.1 HTI R + R VB 1200 ohm 10 K To Dist. Analyzer + VB X1 Instr. Amplifier HTO+ FIGURE 1 – HYBRID AMPLIFIER DISTORTION TEST http://www.belling.com.cn -6- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 FIGURE 2 – ATTENUATOR GAIN versus Vct FIGURE 3 – LEVEL DETECTOR DC TRANSFER CHARACTERISTICS OUTPUT CHANGE (mV) GAIN (dB) Vct – VB (mV) DC INPUT CURRENT (uA) FIGURE 4 – LEVEL DETECTOR AC TRANSFER FIGURE 5 – LEVEL DETECTOR AC TRANSFER CHARACTERISTICS CHARACTERISTICS versus FREQUENCY OUTPUT CHANGE FROM 1.0kHz(mV) OUTPUT CHANGE (mV) INPUT SIGNAL (mVrms) F, FREQUENCY (Hz) FIGURE 6 – RECEIVE ATTENUATOR versus VOLUME FIGURE 7 – RECEIVE ATTENUATION GAIN CONTROL versus Vcc GAIN CHANGE (dB) GAIN (dB) VLC / VB http://www.belling.com.cn Vcc (VOLTS) -7- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 st FIGURE 8 – MICROPHONE AMPLIFIER AND 1 HYBRID FIGURE 9 – INPUT CHARACTERISTICS @ CD, MUT AMPLIFIER OPEN LOOP GAIN AND PHASE INPUT CURRENT (uA) INPUT VOLTAGE (VOLTS) FIGURE 10 – SUPPLY CURRENT versus SUPPLY FIGURE 11 – VB OUTPUT CHARACTERISTICS VOLTAGE FIGURE 12 – VB POWER SUPPLY REJECTION versus FREQUENCY AND VB CAPACITOR http://www.belling.com.cn FIGURE 13 – POWER SUPPLY REJECTION OF THE MICROPHONE AND HYBRID AMPLIFIERS -8- Total 11 Pages 8/15/2006 Wrote by 2006 BL34118 FIGURE 14 – TYPICAL OUTPUT SWING versus Vcc TEMPERATURE CHARACTERISTICS Parameter Typical Value @ 25 °C Typical Change –20 to +60 °C Vcc Supply Current (CD = 0.8 V) 5.0 mA - 0.3 %/°C Vcc Supply Current (CD = 2.0 V) 400 µA -0.4 %/°C VB Output Voltage (Vcc = 5.0 V) 2.1 V +0.8 %/°C Attenuator gain (Max Gain ) +6.0 dB 0.0008 dB/°C Attenuator Gain (Max Attenuation) -46 dB 0.004 dB/°C Attenuator Input Resistance (@ TXI, RXI) 10 kΩ + 0.6 %/°C Dial Tone Detector Threshold 15 mV +20 µV/°C CT Source, Sink Current ± 60 µA -0.15 %/°C Microphone, Hybrid Amplifier Offset Transmit-Receive Switching Threshold Sink Current at RLO1, RLO2, TLO1, TLO2 Closed Loop Gain (HTO- to HTO+) http://www.belling.com.cn 1.0 ± 4.0 µV/°C ± 0.02 %/°C 4.0 µA -10 nA/°C 0 dB 0.001 %/°C 0 mV -9- Total 11 Pages 8/15/2006 Wrote by 2006 270pF VB 5.1k 0.1 5.1k 0.2 5.1k RHI 10k 0.1 0.1 180k RMF Mike MCI 0.02 11 RHF MCO 10 17 TLI2 TXI 9 TXO 8 TLI1 23 7 HTI 0.05 300 51k 0.1 6 Hook Switch HTO- 820 Tip - VB VB Vcc + R - + HTO+ 5 + VB MUT 12 Ring R - Mute VB + VB + Vcc 0.01 Tx Attenuat or APPLICATION CIRCUIT 20uF - ASSEMBLY PACKAGE DIMENSION http://www.belling.com.cn Vcc Vcc 4 - - 10 - Total 11 Pages CD 3 AGC Vcc 100k 47uF Attenuator Control BNM + - + DTD VB - VB VB 15 Filter Rx Attenuat or 220uF 5 8 0.05 4 BL34119 6 RXO 22 VLC 13 20k 0.1 2 21 RXI 0.1 VB 10k FI +1 9.1k Disable 1N4733 5.1V 26 RLI1 FO VB 220k 4700u F 1 0.05 10k 56k Volume Control 3 VB 1 BL34118 8/15/2006 Wrote by 2006 7 RLI2 20 200pF Vcc GND 28 VB 120k 47uF 2.0uF 14 5.0uF RL 100k CPR 27 BNM + CT 110k 2.0uF RLO1 25 uF 5.1k 1000uF TLO1 24 TLO2 18 CPT 16 RLO2 2.0 19 2.0uF BL34118 Unit: inches (mm) SOP 28 http://www.belling.com.cn - 11 - Total 11 Pages 8/15/2006 Wrote by 2006