TS34118
Voice Switched Speakerphone Circuit
SOP-28
DIP-28
Pin Definition:
1. FO
8. TXO
2. FI
9. TXI
10. MCO
3. CD
4. Vcc
11. MCI
5. HTO+
12. MUT
6. HTO-
13. VLC
7. HTI
14. C
T
15. V
B
16. CPT
17. TLI2
18. TLO2
19. RLO2
20. RLI2
21. RXI
22. Gnd
23. TLI1
24. TLO1
25. RLO1
26. RLI1
27. CPR
28. GND
General Description
The TS34118 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 being attenuated by the Receive
background noise monitor circuit. Also included are two line drive 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 filtering 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 TS34118 may be operated from a power supply, or it can be powered from the telephone line, requiring typically
5.0mA. The TS34118 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
Features
●
●
●
●
●
●
●
Improved attenuator gain range: 52dB between
transmit and receive.
Low voltage operation for line-power application
(3V~6.5V).
4-point signal sensing for improved sensitivity
Back ground noise monitors for both transmit and
receive paths.
Compatible with TS34119 speaker amplifier.
Microphone amplifier gain set by external resistors-
mute function included.
Chip disable for active/standby operation.
Ordering Information
Part No.
TS34118CS28 C8
TS34118CD28 C4
Package
SOP-28
DIP-28
Packing
25pcs / Tube
10pcs / Tube
Absolute Maximum Rating
Description
Supply voltage (pin 4)
Voltage at CD (pin 3), MUT (pin 12)
Voltage at VLC (pin 13)
Voltage at TXI (pin 9),RXI (pin 21),FI(pin 2)
Storage temperature range
Value
-1.0, +7.0
-1.0,Vcc +1.0
-1.0,Vcc +0.5
-0.5,Vcc +0.5
-65 to +150
Unit
V
V
V
V
ºC
1/23
Version: A08
TS34118
Voice Switched Speakerphone Circuit
Recommended Operating Conditions
Description
Supply voltage (pin 4) (see Text)
CD input (pin 3), MUT input (pin 12)
I
VB
current (pin 15)
VLC (pin 13)
Attenuator input signal voltage (pin 9,21)
Microphone amplifier, Hybrid amplifier gain
Load current @RXO, TXO (pins 8,22)
@MCO (pin 10)
@HTO-, HTO+ (pin 6,5)
Ambient operating temperature range
Min.
3.5
0
-
0.3xV
B
0
0
0
0
0
-20
Typ.
--
--
--
--
--
--
--
--
--
--
Max.
6.5
Vcc
500
V
B
350
40
±2.0
±1.0
±5.0
+60
Units
V
V
µA
V
mVrms
dB
mA
ºC
Electrical Characteristics
(T
A
=25ºC, Vcc=5.0V, CD≤ 0.8V, unless noted)
Parameter
Power Supply
Vcc supply current (Vcc=6.5V, CD=0.8V)
(Vcc=6.5V, CD=2.0V)
CD input resistance (Vcc=V
CD
=6.5V)
CD input voltage - High
- Low
V
B
output voltage (Vcc=3.5V)
(Vcc=5.0V)
V
B
output resistance (I
VB
=1.0mA)
V
B
power supply rejection ratio (C
VB
=220µF,f=1.0KHz)
Attenuators
(T
A
=+25ºC)
Receive attenuator gain (f=1.0KHz, V
LC
=V
B
)
Rx model, RXI=150mVrms (Vcc=5.0V)
Rx model, RXI=150mVrms (Vcc=3.5V)
Gain change –Vcc=3.5V versus Vcc=5.0V
AGC gain change –Vcc=2.8V versus Vcc=5.0V*
Idle model, RXI=150mVrms
Range (Rx to Tx model)
Volume control range (Rx model, 0.3V
B
<V
LC
<V
B
)
RXO DC voltage (Rx model)
ΔRXO
DC voltage (Rx to Tx model)
RXO high voltage (Iout=-1.0mA RXI=V
B
+1.5V)
RXO low voltage (Iout=+1.0mA, RXI=V
B
-1.0,
Output measured with respect to V
B
)*
RXI input resistance (RXI<350mVrms)
Transmit attenuator gain (f=1.0KHz)
Tx model , TXI=150mVrms
Idle model, TXI=150mVrms
Range (Tx to Rx model)
TXO DC voltage (Tx model)
ΔTXO
DC voltage (Tx to Rx model)
TXO High voltage (Iout=-1.0mA TXI=V
B
+1.5V)
TXO Low voltage (Iout=+1.0mA TXI=V
B
-1.0V,
Output measured with respect to V
B
)*
2/23
Symbol
Icc
R
CD
V
CDH
V
CDL
V
B
R
OVB
PSRR
Min
--
--
50
2.0
0
--
1.8
--
--
Typ
5.5
600
90
--
--
1.3
2.1
400
54
Max
8.0
800
--
Vcc
0.8
--
2.4
--
--
Unit
mA
µA
KΩ
V
V
V
Ω
dB
G
RX
G
RX
ΔG
RX1
ΔG
RX2
G
RX1
ΔG
RX3
V
CR
V
RXO
ΔV
RXO
V
RXOH
V
RXOL
R
RXI
G
TX
G
TXI
ΔG
TXI
V
TXO
ΔV
TXO
V
TXOH
V
TXOL
+4.0
+4.0
-0.5
--
-22
49
27
--
--
3.7
--
7.0
+4.0
-22
49
--
--
3.7
--
+6.0
+6.0
0
-25
-20
52
35
VB
±10
--
-1.5
10
+6.0
-20
52
V
B
±30
--
-1.5
+8.0
+8.0
+0.5
-15
-17
54
--
--
±150
--
-1.0
14
+8.0
-17
54
--
±150
--
-1.0
dB
dB
V
mV
V
V
KΩ
dB
V
mV
V
V
Version: A08
TS34118
Voice Switched Speakerphone Circuit
Electrical Characteristics
-
Continue
Parameter
Attenuators-continued
(T
A
=+25ºC)
TXI input resistance (TXI<350mVrms)
Gain tracking (G
RX
+ G
TX
, @ Tx, Idle, Rx)*
Attenuator Control
(T
A
=+25ºC)
Rx model (V
LC
=V
B
)
dle model
Tx model
C
T
source current(switching to Rx mode)
C
T
sink current(switching to Tx mode)
C
T
slow idle current
C
T
fast idle internal resistance
Output offset (V
MCO
-V
B
, feedback R=180KΩ)
Open loop gain (f<100Hz)
C
T
voltage (pin 14-V
B
)
V
CT
I
CTR
I
CTT
I
CTS
R
FI
MCOvos
A
VOLM
--
--
--
-85
+40
--
1.5
-50
70
--
3.7
--
--
-55
--
50
2.0
0
-20
-30
60
--
-0.35
--
3.7
--
3.7
--
--
+240
0
-240
-60
+60
0
2.0
0
80
1.0
--
--
-40
--
-68
90
--
--
0
0
80
1.0
0
-30
--
--
--
--
0.3
--
--
--
-40
+85
--
3.6
+50
--
--
--
200
--
--
--
--
Vcc
0.8
+20
+30
--
--
+0.35
--
--
250
--
450
--
mV
µA
µA
µA
KΩ
mV
dB
MHz
V
mV
nA
dB
KΩ
V
V
mV
mV
dB
MHz
dB
nA
V
mV
V
mV
%
R
TXI
G
TR
7.0
--
10
±0.1
14
--
KΩ
dB
Symbol
Min
Typ
Max
Unit
Microphone Amplifier
(T
A
=+25ºC,V
MUT
≤0.8V,A
VCL
=31dB unless otherwise noted)
Gain bandwidth
GBW
M
Output High voltage (Iout=-1.0mA, Vcc=5.0V)
V
MCOH
Output Low voltage (Iout=+1.0mA)
V
MCOL
Input bias current (@MCI)
I
BM
Muting (ΔGain) (f=1.0KHz, V
MUT
=2.0V)
GMT
(300Hz<f<10KHz)
MUT input resistance (Vcc=V
MUT
=6.5V)
R
MUT
MUT Input-High
V
MUTH
MUT Input-Low
V
MUTL
Hybrid Amplifiers
(T
A
=+25ºC)
HTO-offset(V
HTO-
-V
B
, Feedback R=51KΩ)
H
VOS
HTO- to HTO+ offset (Feedback R=51KΩ)
HB
VOS
Open loop gain(HTI to HTO-, f<100Hz)
A
VOLH
Gain bandwidth
GBW
H
Closed loop gain(HTO- to HTO+)
A
VCLH
Input bias current(@HTI)
I
BH
HTO- High voltage (Iout=-5.0mA)
V
HT-H
HTO- Low voltage (Iout=+5.0mA)
V
HT-L
HTO+ High voltage (Iout=-5.0mA)
V
HT+H
HTO+ Low voltage (Iout=+5.0mA)
V
HT+L
Distortion(300Hz<f<10KHz, see Figure 1)
THD
H
Level Detectors and Background Noise Monitors
(T
A
=+25ºC)
Transmit-Receive switch threshold
(Ratio of current at RLI1 + RLI2 to 20µA
I
TH
at TLI1 + TLI2 to switch from Tx to Rx)
Source current at RLO1, RLO2, TLO1, TLO2
I
LSO
Sink current at RLO1, RLO2, TLO1, TLO2
I
LSK
CPR, CPT output resistance (Iout=1.5mA)
R
CP
CPR, CPT leakage current
I
CPLK
0.8
--
--
--
--
1.0
-2.0
4.0
35
-0.2
1.2
--
--
--
--
mA
µA
Ω
µA
3/23
Version: A08
TS34118
Voice Switched Speakerphone Circuit
Electrical Characteristics
-
Continue
Parameter
Filter
(T
A
=+25ºC)
Voltage offset at FO (V
FO
-V
B
, 220KΩ from V
B
to FI)
FO sink current
FI bias current
System Distortion
(T
A
=+25ºC, f=1.0KHz)
Rx mode (from FI to RXO, FO connected to RXI)
Symbol
FO
VOS
I
FO
I
FI
THD
R
Min
-200
150
--
--
Typ
-90
260
-50
0.5
Max
0
400
--
3.0
Unit
mV
µA
nA
%
Tx mode (from MCI to HTO-/HTO+, includes
THD
T
--
0.8
3.0
%
Tx attenuator)
* All currents into a device pin are positive, those out of a pin are negative. Algebraic convention rather than magnitude
is used to define limits.
Simplified Block Diagram
Temperature Characteristics
Parameter
Vcc supply current (CD=0.8V)
Vcc supply current (CD=2.0V)
V
B
output voltage (Vcc=5.0V)
Attenuator gain (Max Gain)
Attenuator gain (Max attenuation)
Attenuator input resistance (@ TXI, RXI)
Dial tone detector threshold
CT source, sink current
Microphone, Hybrid amplifier offset
Transmit-Receive switching threshold
Sink current at RLO1, RLO2, TLO1, TLO2
Closed loop gain (HTO- to HTO+)
Typical Value @25
ºC
5.0mA
400µA
2.1V
+6.0dB
-46dB
10KΩ
15mV
±60µA
0 mV
1.0
4.0µA
0 dB
Typical Change –20 to +60
ºC
-0.3%/ºC
-0.4%/ºC
+0.8%/ºC
0.0008dB/ºC
0.004dB/ºC
+0.6%/ºC
+20µV/ºC
-0.15%/ºC
±4.0µV/ºC
±0.02%/ºC
-10nA/ºC
0.001%/ºC
4/23
Version: A08
TS34118
Voice Switched Speakerphone Circuit
Pin Function Description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
Name
FO
FI
CD
Vcc
HTO+
HTO-
HTI
TXO
TXI
MCO
MCI
MUT
Description
Filter output. Output impedance is less than 50 ohms.
Filter input. Input impedance is greater than 1.0Mohm.
Chip Disable. A logic low(<0.8V) sets normal operation. A logic high (>2.0V) disables the IC to
conserve power. Input impedance is norminally 90KΩ.
A supply voltage of +2.8 to +6.5 volts is required, at
≈5.0mA.
As Vcc falls from 3.5 to 2.8volts,
an AGC circuit reduces the receive attenuator gain by
≈25dB
(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.
Output of the first hybrid amplifier. The gain of the amp is set by external resistors.
Input and summing node for the first hybrid amplifier . DC level is≈V
B.
Output of the transmit attenuator. DC level is approximately V
B.
Input to the transmit attenuator. Max. Signal level is 350m Vrms . Input impedance is 10KΩ.
Output of the microphone amplifier. The gain of the amplifier is set by external resistors.
Input and summing node of the microphone amplifier. DC level is≈ V
B.
Mute input. A logic low(<0.8V) sets normal operation. A logic high (>2.0V) mutes the
microphone amplifier without affecting the rest of the circuit. Input impedance is norminally
90KΩ.
Volume control input. When VLC=V
B
, the receive attenuator is at maximum gain when in the
receive mode. When VLC=0.3V
B
, the receive gain is down 35dB. Does not affect the transmit
mode.
An RC at this pin sets the response time for the circuit to switch modes.
An output voltage≈Vcc/2. 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 transmit background monitor.
Input to the transmit level detector on the mike/speaker side.
Output of the transmit level detector on the mike/speaker side, and input to the transmit
background monitor.
Output of the receive level detector on the mike/speaker side.
Input to the receive level detector on the mike/speaker side.
Input to the receive attenuator and dial tone detector. Max input level is 350mV RMS. Input
impedance is
≈10KΩ.
Output of the receive attenuator. DC level is approximately V
B
.
Input to the transmit level detector on the line side.
Output of the transmit level detector on the line side.
Output of the receive level detector on the line side, and input to the receive background
monitor.
Input to the receive level detector on the line side.
An RC at this pin sets the time constant for the receive background monitor.
Ground pin for the entire IC.
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
VLC
C
T
V
B
CPT
TLI2
TLO2
RLO2
RLI2
RXI
RXO
TLI1
TLO1
RLO1
RLI1
CPR
GND
5/23
Version: A08
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