BELLING BL34118 Voice switched speakerphone circuit Datasheet

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
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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.
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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
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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)
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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)
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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
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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
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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
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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+)
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1.0
± 4.0 µV/°C
± 0.02 %/°C
4.0 µA
-10 nA/°C
0 dB
0.001 %/°C
0 mV
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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
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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
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- 11 -
Total 11 Pages
8/15/2006
Wrote by 2006
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