U4082B_15 [UTC]
VOICE SWITCHED SPEAKER-PHONE CIRCUIT;
| 型号： | U4082B_15 |
| 厂家： | 
Unisonic Technologies |
| 描述： | VOICE SWITCHED SPEAKER-PHONE CIRCUIT |
| 文件： | 总13页 (文件大小：352K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
UNISONIC TECHNOLOGIES CO., LTD
U4082B
LINEAR INTEGRATED CIRCUIT
VOICE SWITCHED
SPEAKER-PHONE CIRCUIT
DESCRIPTION
DIP-28
As a voice switched speaker-phone integrated circuit, the UTC
U4082B includes the necessary amplifiers, attenuators, level
detectors and control algorithm.
To form the UTC U4082B’s internal circuit, there is an internal
microphone amplifier with adjustable gain and mute control, internal
transmit and Receive attenuators (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.
SOP-28
The dial tone can be pretended from being attenuated by the
receive background noise monitor circuit by a dial tone detector.
There are also 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 for other filtering functions, and especially
to filter out 60Hz noise in the receive channel.
The UTC U4082B which requiring typically 5mA may be operated
from a power supply, or it can be powered from the telephone line.
FEATURES
* Attenuator gain range: 52dB (between Transmit and Receive)
* For line-powered applications : 3~6.5V low voltage operation
* For improved sensitivity :4-point signal sensing
* For Transmit and Receive paths: background noise monitors
* External resistors set microphone amplifier gain
* Mute function included
* Chip disable: active or standby operation
* During dial tone presence: dial tone detector to inhibit receive idle
mode
ORDERING INFORMATION
Ordering Number
Package
Packing
Lead Free Plating
U4082BL-D28-T
U4082BL-S28-T
U4082BL-S28-R
Halogen Free
U4082BG-D28-T
U4082BG-S28-T
U4082BG-S28-R
DIP-28
SOP-28
SOP-28
Tube
Tube
Tape Reel
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U4082B
LINEAR INTEGRATED CIRCUIT
PIN DESCRIPTION
PIN NO
PIN NAME
DESCRIPTION
1
2
FO
FI
Output of filter. The output impedance is less than 50Ω.
Input of filter. The input impedance is less than 1MΩ.
Chip Disable input .A logic low (voltage lower than 0.8V) sets normal operation. A logic
high (voltage higher than 2V) disable the IC. This pin’s input impedance is 90 KΩ
nominally.
3
4
CD
This pin requires a supply voltage of +2.8V ~ +6.5V at 5mA. After VCC falls from 3.5V ~
2.8V, when in the receive mode, an AGC circuit reduces the receive attenuator gain by
25dB.
VCC
5
6
HTO+
HTO-
The output of the second hybrid amplifier. This amplifier’s gain is internally set at -1.
Output of the first hybrid amplifier. This amplifier’s gain of the amplifier is set by
external resistors.
7
8
HTI
The first hybrid amplifier’s input and summing node. DC level is about equal to VB.
The transmit attenuator’s output. DC level is about VB.
TXO
The transmit attenuator’s input. It’s maximum signal level is 350 mVrms. The input
impedance is 10Kꢀ.
9
TXI
10
11
MCO
MCI
The microphone amplifier’s output. This amplifier’s gain is set by external resistors.
The summing node of the microphone’s input. DC lever is VB.
Input of mute. A logic low (voltage lower than 0.8V) sets the circuit normal operation. A
logic high (voltage higher than 2V) mutes the microphone amplifier, but it doesn’t affect
the rest of the circuit. The input impedance is 90 K ohms.
12
13
MUT
VLC
The input of Volume control. In the receive mode, when VLC=VB, the receive
attenuator is at maximum gain. The receive gain is down 35dB when VLC=0.3dB, and
it does not effect the transmit modes.
14
15
CT
VB
At this pin, to switch modes, the RC sets the response time for the circuit.
In this pin, there’s an output voltage=Vcc/2 which is a system AC ground and biases
the volume control. What required is a filter capacitor.
16
17
CPT
TLI2
The time constant for the transmit background side can be set by the RC at this pin .
The input to the transmit level detector which is on the microphone/ speaker side.
The output to the transmit level detector which is on the microphone/ speaker side.
Also the input to the transmit background monitor.
18
TLO2
19
20
RLO2
RLI2
The Output of the receive level detector which is on the microphone/ speaker side
The input to the receive level detector which is on the microphone/ speaker side
The input to the receive attenuator and dial tone detector. In this pin, the maximum
input level is 350mVrms,and the input impedance is 10Kꢀ.
21
RXI
22
23
RXO
TLI1
The output of the receive attenuator. This pin’s DC level is VB.
The input to the transmit level detector which is on the line side.
The output to the transmit level detector which is on the line side, and also the input to
the transmit background monitor.
24
TLO1
25
26
27
28
RLO1
RLI1
CPR
GND
The output of the receive level detector which is on the line side.
The input to the receive level detector which is on the line side.
The time constant for the receive background monitor can be set by the RC at this pin.
Ground.
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U4082B
LINEAR INTEGRATED CIRCUIT
BLOCK DIAGRAM
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U4082B
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING (TA=25°С, unless otherwise specified. Voltages referred to pin 22)
PARAMETER
SYMBOL
VCC
RATINGS
-1~7
UNIT
V
Supply Voltage
Voltage at Pin 3
V3
-1~VCC+1
-1~VCC +1
-1~VCC+0.5
-0.5~ VCC+0.5
-65~+150
V
Voltage at Pin 12 ( mute)
Voltage at Pin 13 ( VLC)
Voltage at Pin 9, Pin 21, and Pin 2
Storage Temperature
V12
V
V13
V
V9, 21, 2
TSTR
V
°С
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
RECOMMENDED OPERATION CONDITIONS
PARAMETER
SYMBOL
RATINGS
3.5~6.5
UNIT
V
Supply Voltage
Voltage at Pin 3
V4
V3
0~ VCC
V
Voltage at Pin 12 ( MUTE)
V12
0~ VCC
V
0.3×VB~VB
Voltage at Pin 13 ( VLC)
V13
V
IVB Current ( Pin 15)
IVB
500
350
µA
Attenuator Input Signal Voltage at Pin 9, Pin 21
V9, V21
mVrms
mA
mA
mA
°С
RXO, TXO(Pin8, Pin 22)
MCO(Pin 10)
HTO-, HTO+(Pin 6, Pin5)
0~+-2
0~+-1
0~+-0.5
-20~+60
Load Current
Ambient Operating Temperature
TOPR
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U4082B
LINEAR INTEGRATED CIRCUIT
ELECTRICAL CHARACTERISTICS (TA=25°C, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN TYP MAX UNIT
Supply Voltages
V+ Supply Current
CD Input Resistance
VCC=6.5V, CD=0.8V
VCC =6.5V, CD=2V
VCC =VCD=6.5V
5.5
8
mA
μA
kꢀ
V
ICC
600 800
RCD
VCDH
VCDL
50
2
90
High
VCC
0.8
1.3
CD Input Voltage
VB Output Voltage
Low
V
VCC =3.5V
VCC =5V
IVB=1mA
V
VB
1.8
2.1
400
54
2.4
VB Output Resistance
VB Power Supply Rejection Ratio
Attenuators
ROVB
ꢀ
PSRR CVB=220µF, f=1kHz
dB
RX Mode, RXI=150mVrms
GRX
GRX
VCC=5V
4
4
6
6
8
8
dB
dB
RX Mode, RXI=150mVrms
Gain Change
VCC =3.5V
Receive Attenuator
Gain
(f=1kHz, VLC=VB)
ΔGRX1 VCC =3.5V vs. VCC =5V
-0.5
0
+0.5 dB
AGC Gain Change
ΔGRX2 VCC =3.5V vs. VCC =5V
-25
-20
52
35
VB
-15
-17
54
dB
dB
dB
dB
V
Idle Mode, RXI=150mVrms
RX to TX Mode Range
GRXI
ΔGRX3
VCR
-22
49
Volume Control Range
RXO DC Voltage
27
VRXO
RX Mode
ΔRXO DC Voltage
RXO High Voltage
ΔVRXO RX to TX Mode
+-10 +-150 mV
V
VRXOH
VRXOL
RRXI
IOUT=-1mA, RXI=VB+1.5V
3.7
7
IOUT=+1mA, RXI=VB-1V,
Output Measured with
Respect to VB
RXO Low Voltage
-1.5
10
-1
V
RXI Input Resistance
RXI<350mVrs
14
kꢀ
Transmit Attenuator Gain (f=1kHz)
TX Mode, TXI=150mVrms
Idle Mode, TXI=150mVrms
TX to Rx Mode Range
TXO DC Voltage
GTX
GTXI
4
6
8
dB
dB
dB
V
-22
49
-20
52
-17
54
ΔGTXI
VTXO
TX
VB
ΔTXO DC Voltage
TXO High Voltage
ΔVTXO
VTXOH
TX to RX Mode
+-30 +-150 mV
V
IOUT=-1mA, TXI=VB+1.5V
IOUT =+1mA, TXI=VB-1V,
Output Measured with
Respect to VB
3.7
7
TXO Low Voltage
VTXOL
-1.5
-1
V
TXI Input Resistance
Gain Tracking
RTXI
GTR
TXI<350mVrs
GRX+GTX, @TX, IDIE, RX
10
14
kꢀ
+-0.1
dB
Attenuator Control
RX Mode
VLC=VB
240
0
mV
mV
mV
µA
µA
µA
kꢀ
nA
CT Voltage ( CT-VB)
Idle Mode
TX Mode
-240
-60
CT Source Current
ICTR
ICTT
ICTS
RFI
(Switching to RX Mode)
(Switching to TX Mode)
-85
-40
CT Sink Current
+40 +60 +85
0
CT Slow Idle Current
CT Fast Idle Internal Resistance
VLC Input Current
1.5
2
3.6
IVLC
VDT
-60
15
Dial Tone Detector Threshold
10
20
mV
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U4082B
LINEAR INTEGRATED CIRCUIT
ELECTRICAL CHARACTERISTICS(Cont.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN TYP MAX UNIT
Microphone Amplifier ( VMUT< 0.8V, AVCL=31dB, unless otherwise specified)
Output Offset
MCOVOS VMCO-VB, RF=180 kꢀ
-50
70
0
80
1
50
mV
dB
Open Loop Gain
Gain Bandwidth
Output High Voltage
Output Low Voltage
Input Bias Current
AVOLM
GBWM
F<100Hz
MHz
V
VMCOH IOUT =1mA, VCC=5V
3.7
-55
VMCOL
IBM
IOUT =1mA
200 mV
nA
@MCI
-40
f=1kHz, VMUT=2V
300Hz<f<10kHz
VCC=VMUT=6.5V
Muting(ΔGain)
GMT
dB
-68
90
MUT Input Resistance
MUT High Input Voltage
RMUT
50
2
kꢀ
Vcc
0.8
VMUTH
V
MUT Low Input Voltage
Distortion
VMUTL
THDM
0
V
300Hz<f<10kHz
0.15
%
HYBID AMPLIFIER
HTO-Offset
HVOS
HBVOS
AVOLH
GBWH
AVCLH
IBH
VHTO-~VB, RF=51kꢀ
RF =51kꢀ
-20
-30
60
0
0
20
30
mV
mV
dB
HTO- to HTO+ Offset
Open Loop Gain
Gain Bandwidth
HTI to HTO-, F<100Hz
80
1
MHz
Closed Loop Gain
Input Bias Current(@HTI)
HTO- High Voltage
HTO- Low Voltage
HTO+ High Voltage
HTO+ Low Voltage
Distortion
HTO- to HTO+
-0.35
3.7
0
0.35 dB
-30
nA
VHT-H
VHT-L
VHT+H
VHT+L
THDM
IOUT =-5mA
V
250 mV
V
IOUT =+5mA
IOUT =-5mA
3.7
IOUT =+5mA
300Hz<f<10kHz
450 mV
%
0.3
1
Level Detectors And Background Noise Monitors
Transmit-Receive Switching
Threshold( Ratio of Current at RLI1+RLI2 to
20μA at TLI1+TLI2 to Switch from Tx to Rx)
Source Current at RLO1, RLO2, TLO1, TLO2
Sink Current at RLO1, RLO2, TLO1, TLO2
CPR, CPT Output Resistance
CPR, CPT Leakage Current
Filter
ITH
0.8
1.2
ILSO
ILSK
-2
4
mA
µA
ꢀ
RCP
ICPLK
IOUT =1.5mA
35
-0.2
µA
Voltage Offset at FO
FOVOS
IFO
VFO-VB, 220kꢀ from VB to FI
-200 -90
0
mV
µA
nA
FO Sink Current
150 260 400
-50
FI Bias Current
IFI
SYSTEM Distortion (f=1kHz)
from FI to RXO
FO connected to RXI
,
RX Mode
TX Mode
THDR
THD
0.5
0.8
3
3
%
%
from MCI to HTO-/HTO+
includes TX attenuator
,
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U4082B
LINEAR INTEGRATED CIRCUIT
TEMPERATURE PARAMETERS
PARAMETER
TYP RATINGS (TA=25°С)
TYP CHANGE
-0.3
UNIT
%/°С
%/°С
%/°С
dB/°С
dB/°С
%/°С
µV/°С
%/°С
µV/°С
%/°С
nA/°С
%/°С
VCC Supply Current(CD=0.8V)
VCC Supply Current(CD=2V)
5mA
400µA
2.1V
6
-0.4
VB Output Voltage (VCC =5V)
+0.8
Attenuator Gain (Max Gain)
0.0008
0.004
0.6
Attenuator Gain (Max Attenuation)
Attenuator Input resistance
-46dB
10kꢀ
15mV
±60µA
0mV
1
Dial Tone Detector Threshold
CT Source, Sink Current
20
-0.15
±4
Microphone, Hybrid Amplifier Offset
Transmit-Receive Switching Threshold
Sink Current at RLO1, RLO2, TLO1, TLO2
Closed Loop Gain( HTO- to HTO+)
±0.02
-10
4µA
0dB
0.001
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U4082B
LINEAR INTEGRATED CIRCUIT
FUNCTIONAL DESCRIPTION
INTRODUCTION
Between operation of a speakerphone and a handset, the fundamental difference is that of half-duplex versus
full-duplex. The UTC U4082B includes the necessary level detectors, attenuators, and switching control for a
properly operating speakerphone. The detection sensitivity and timing can be externally controlled. The UTC
U4082B also provides background noise monitors to make the circuit insensitive to room and line noise, hybrid
amplifier to interface to Tip and Ring, the microphone amplifier, and other associated functions.
ATTENUATORS
The transmit and receive attenuators are complementary in function, and they are never both fully on or both
fully off. For example, when one is at maximum gain: +6dB, the other is at maximum attenuation: -46dB, and vice
versa. But sum of their gains remains constant at -40dB typically. To control the transmit and receive paths to
provide the half-duplex operation required in speakerphone is the attenuators’ purpose. The attenuators are
non-inverting, have a -3dB (from max gain) frequency of ~100kHz, their input impedance of each one is nominally
10kꢀ, and to prevent distortion, their input signal should be limited to 350 mVrms(same as 990mvp-p). After the
output current limit (typically 2.5mA) is reached, the output impedance is<10ꢀ.
VB
10kꢀ
TXI/RXI
To Attenuator Input
4.0kꢀ
96Kꢀ
These attenuators can be controlled by the Control Block’s output signal. When the CT pin which measures the
signal is at +240mV with respect to VB, the circuit is in the receive mode and so receive attenuator is at +6dB. When
the CT voltage is equal to VB, the circuit is in an idle mode, and it also causing the attenuators’ gains to be halfway
between their fully on and fully off positions (typical -20 dB each). The most direct method to monitor the circuit’s
mode is monitoring the CT voltage (with respect to VB).
LEVEL DETECTORS
There are two level detectors on the receive side and two level detectors on the transmit side. The terms in
parentheses form one system, and the other terms form the second system. All the four level detectors are high
amplifiers which have back-to-back diodes in the feedback path, and then it is resulting in non-linear gain, which
permits operation over a wide dynamic range of speech levels. TLI1, TLI2, RLI1, and RLI2, the external resistor and
capacitor determine the sensitivity of each level detector. Through a diode each output charges an external capacitor
and limiting resistor, thus providing a DC representation of the input AC signal level. The capacitor and an internal
350ꢀ resistor provide the outputs’ quick rise time. And an internal current source and the capacitor set a slow decay
time. On the receive side, RLI1 is at the receive input receiving the same signal as at Tip and Ring, and RLI2 is at
the output of the speaker amplifier. On the transmit side, TLI2 is at the microphone amplifier, while TLI1 is at the
hybrid output.
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U4082B
LINEAR INTEGRATED CIRCUIT
FUNCTIONAL DESCRIPTION(Cont.)
BACKGROUND NOISE MONITORS
To distinguish speech (consists of bursts) from background noise (a relatively constant signal level) is the main
purpose of the background noise monitors. There is one background noise monitor for the receive path and another
one for the transmit path. The receive background noise monitor is operated on by the RLI1-RLO1 level detector, as
same as the transmit background noise monitor is operated on by the TLI2-TLO2 level detector. By storing a DC
voltage representative of the respective noise levels in capacitors at CPR and CPT, the background noise can be
monitored. At these pins, the voltages have slow rise times which determined by the external RC, but fast decay
times. The voltage at the non-inverting input of the monitor’s output comparator won’t be more positive than the
voltage at CPR/CPT when the signal at RLI1/TLI2 changes slowly. But while speech is present, it will rise quicker
than the voltage at the inverting input, causing its output to change. The term’s output is sensed by the attenuator
Control Block.
VOLUME CONTROL
At VLC (pin 13) is the volume control input which is sensed as a voltage with respect to VB. Only in the receive
mode the volume control affects the attenuators. In the receive mode, the receive attenuator’s gain will be +6dB, and
the transmit attenuator’s gain will be -46dB when VLC is equal to VB. When VLC is reduced below VB, the receive
attenuator’s gain is reduced, and the transmit attenuator’s gain is increased, but the sum of them tow remains
constant. Out of the pin VLC, the bias current is typically 60nA.
DIAL TONE DETECTOR
This detector is a comparator with one side connected to RXI and one side input connected to VB with a 15mV
offset. Under this situation: the circuit is in the receive mode, and the incoming signal is greater than 15Mv, the
comparator’s output will change, disabling the receive idle mode. Then receive attenuator will be at a setting only
determined by the volume control.
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U4082B
LINEAR INTEGRATED CIRCUIT
FUNCTIONAL DESCRIPTION(Cont.)
AGC
The AGC circuit only affects the circuit under such situation: when the circuit is in the receive mode, and when
CC is less than 3.5v. As while as VCC falls below 3.5 volts, the transmit path attenuation changes so that the sum of
V
the transmit and receive gains remains constant.
ATTENUATOR CONTROL BLOCK
This block has the seven:
* C1: The output of the comparator operated by RLO2 and TLO2 (here means in microphone/ speaker side).
* C2: The output of the comparator operated by RLO1 and TLO1 (here means Tip/ Ring side).
* C3: The output of the transmit background noise monitor.
* C4: The output of the receive background noise monitor.
* Volume control
* Dial tone detector
* AGC circuit
The C1~C4 effect is as follows:
INPUTS
OUTPUT
C1
TX
TX
RX
RX
TX
TX
RX
RX
C2
TX
RX
TX
RX
TX
RX
TX
RX
C3
1
C4
X
Y
Y
1
Transmit Mode
Fast Idle Mode
Fast Idle Mode
Receive Mode
Slow Idle Mode
Slow Idle Mode
Slow Idle Mode
Slow Idle Mode
Y
Y
X
0
X
0
0
0
0
X
0
Switching to the full transmit or receive from any other mode is at the fast rate (~30 ms).
X :Don’t care
Y :C3,C4 are not both 0
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U4082B
LINEAR INTEGRATED CIRCUIT
FUNCTIONAL DESCRIPTION(Cont.)
Definition of the above is as follows:
Trems
Definition
Transmit
The transmit attenuator is fully on: +6dB. And the receive attenuator is at max. attenuation :-46dB
Both attenuators are controlled by the volume control. At max. Volume the receive attenuator is fully
on: +6dB, and the transmit attenuator is at max.attenuation:-46dB.
Receive
Both transmit and receive speech are present in approximately equal levels.
The attenuators are quickly switched to idle until one speech level dominates the other.
Speech has ceased in both transmit and receive paths. The attenuators are then slowly switched to
the idle mode.
Fast Idle
Slow Idle
A summary of the truth table is:
1. Under all the below situations the circuit will switch to transmit :
(1) Both transmit level detectors sense signals relative to the respective receive level detectors
TLI1 versus RLI1, TLI2 versus RLI2
(2) The transmit background noise monitor indicates the presence of speech.
2. Under all the below situations the circuit will switch to receive
(1) Both receive level detectors sense higher signal levels relative to the respective transmit level detectors
(2) The receive background noise monitor indicates the presence of speech.
3. Under all the below situations the circuit will switch to the fast Idle mode:
(1) If the level detectors disagree on the relative strengths of the signal levels
(2) At least one of the background noise monitor indicates speech.
There are two conditions which can cause the fast idle mode to occur:
(A) When both talkers are attempting to gain control of the system by talking at the same time
(B) When one talker is in a very noisy environment, forcing the other to continually over-ride that noise level. In
general, the fast idle mode will occur infrequently.
4. Under any of the below situations the circuit will switch to the slow idle mode
(1) Both talkers are quiet( no speech present)
(2) When one talker’s speech level is continuously over-ride by noise at the other speaker’s location.
CT pin (pin14) determine the time required to switch the circuit between transmit, receive, fast idle, and slow
idle.
A schematic of the CT circuitry operates as follows:
*
*
RT =120kꢀ (typ.), and CT =5µF (typ.).
Switching to the receive mode
I1 is turned on; I2 is off,
Charging the external capacitor to +240mV above VB
An internal clamp prevents further charging of the capacitor).
Switching to the transmit mode
*
I2 is turned on; I1 is off,
Bringing down the voltage on the capacitor to -240mV with respect VB.
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U4082B
LINEAR INTEGRATED CIRCUIT
FUNCTIONAL DESCRIPTION(Cont.)
*
Switch to idle quickly,
The current sources are turned off,
The internal 2kꢀ resistor is switched in
Discharging the capacitor to VB with a time = 2kꢀ x CT.
Switching to idle slowly
*
The current sources are turned off
The switch at the 2kꢀ resistor is open
Discharging the capacitor to VB through the external resistor RT with a time=RT x CT.
MICROPHONE AMPLIFIER
While the inverting input and the output are pinned out, pins 10/11,the microphone amplifier, has the
non-inverting input internally connected to VB. This amplifier’s open loop gain is typically 80dB when f<100Hz, and
the gain bandwidth is typically 1MHz. Its maximum output swing (p-p) is typically 1 volt. MCI’s input bias current is
typically 40nA out of the pin.
HYBRID AMPLIFIER
At HTO+, HTO-, and HTI, the two hybrid amplifiers provide the two-to-four wire converter for interfacing to the
telephone line. The first amplifier’s gain is set by external resistor, and the first amplifier’s output drives the second
amplifier (gain of -1).
FILTER
The external components determined the operation of the filter circuit.
POWER SUPPLY, VB, and CHIP DISABLE
For normal operation the power supply voltage is to be between 3.5v and 6.5v, but with reduced operation the
VCC is possible 2.8 volts. VB’s output voltage is ~ (Vcc-0.7)/2, and also provides the AC ground.
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U4082B
LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATION CIRCUIT
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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