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TS34118CS28

Taiwan Semiconductor

1 Version: E1608

Voice Switched Speakerphone Circuit

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.

● Compliant to RoHS Directive 2011/65/EU and in

accordance to WEEE 2002/96/EC.

● Halogen-free according to IEC 61249-2-21

APPLICATION

● Hands-free operation system

● VOIP phone

SOP

Pin Definition:

1. FO 8. TXO 15. V

22. Gnd

2. FI 9. TXI 16. CPT 23. TLI1

3. CD

10. MCO

17. TLI2

24. TLO1

4. Vcc

11. MCI 18. TLO2 25. RLO1

5. HTO+

12. MUT 19. RLO2 26. RLI1

6. HTO-

13. VCI 20. RLI2 27. CPR

7. HTI

14. C

21. RXI 28. GND

Notes: MSL 3 (Moisture Sensitivity Level) per J-STD-020

ABSOLUTE MAXIMUM RATINGS

= 25°C unless otherwise specified)

(Note 1)

PARAMETER SYMBOL LIMIT UNIT

Supply voltage

(pin 4)

-1.0, +7.0

Voltage at CD

(pin 3)

, MUT

(pin 12)

CD,

MUT

-1.0,Vcc +1.0

Voltage at VCI

(pin 13)

-1.0,Vcc +0.5

Voltage at TXI

(pin 9)

,RXI

(pin 21)

,FI

(pin 2)

TXI,

RXI,

-0.5,Vcc +0.5

Storage temperature range

STG

-65 to +150

°C

Summary of content (20 pages)

PAGE 1
TS34118CS28 Taiwan Semiconductor Voice Switched Speakerphone Circuit DESCRIPTION FEATURES The TS34118 Voice Switched Speakerphone Circuit ● Improved attenuator gain range: 52dB between incorporates the necessary amplifiers, attenuators, transmit and receive. level detectors, and control algorithm to form the heart ● Low voltage operation for line-power application of a high quality hands-free speakerphone system. (3V~6.5V).
PAGE 2
TS34118CS28 Taiwan Semiconductor RECOMMENDED OPERATING CONDITION (TA = 25°C unless otherwise specified) (Note 4) PARAMETER Supply voltage CD input (pin 3) IVB current VCI (pin 4) (see Text) , MUT input (pin 12) (pin 15) (pin 13) Attenuator input signal voltage (pin 9,21) SYMBOL MIN TYP MAX UNIT VS 3.5 -- 6.5 V VCD, VMUT 0 -- VCC V IVB - -- 500 μA VCI 0.3xVB -- VB V VAIS 0 -- 350 mVrms 0 -- 40 dB 0 0 0 ---- ±2.0 ±1.0 ±5.
PAGE 3
TS34118CS28 Taiwan Semiconductor ELECTRICAL SPECIFICATIONS (TA = 25°C unless otherwise specified) PARAMETER CONDITION SYMBOL MIN TYP MAX UNIT IO=-1mA TXI=VB+1.5V IO=+1mA TXI=VB-1.0V, Output measured with respect to VB TXI<350mVrms GRX + GTX, @ TX, Idle, RX VTXOH 3.7 -- -- V VTXOL -- -1.5 -1.0 V RTXI GTR 7.0 -- 10 ±0.1 14 -- kΩ dB VCT ---- +240 0 -240 ---- mV ICTR ICTT ICTS RFI -85 +40 -1.5 -60 +60 0 2.0 -40 +85 -3.6 μA μA μA kΩ -50 0 +50 mV 70 -3.7 ---55 -50 2.0 0 80 1.
PAGE 4
TS34118CS28 Taiwan Semiconductor ELECTRICAL SPECIFICATIONS (TA = 25°C unless otherwise specified) PARAMETER CONDITION Level Detectors and Background Noise Monitors RLO1, RLO2, TLO1, Source current TLO2 RLO1, RLO2, TLO1, Sink current TLO2 CPR, CPT output resistance IO=1.5mA CPR, CPT leakage current SYMBOL MIN TYP MAX UNIT ILSO -- -2.0 -- mA ILSK -- 4.0 -- μA RCP ICPLK --- 35 -0.2 --- Ω μA FOVOS -200 -90 0 mV IFO 150 260 400 μA IFI -- -50 -- nA THDR -- 0.5 3.
PAGE 5
TS34118CS28 Taiwan Semiconductor ORDERING INFORMATION PART NO. PACKAGE PACKING TS34118CS28 RDG SOP-28 1,500pcs / 13”Reel PIN DESCRIPTION PIN NO. NAME FUNCTION 1 FO Filter output. Output impedance is less than 50Ω 2 FI 3 CD 4 VCC 5 HTO+ 6 HTO- Filter input. Input impedance is greater than 1MΩ. 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 90kΩ. A supply voltage of +2.8V to +6.
PAGE 6
TS34118CS28 Taiwan Semiconductor TYPICAL APPLICATION CIRCUIT Figure 1. Hybrid Amplifier Distortion Test Figure 2.
PAGE 7
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION The fundamental difference between the operation of a speakerphone and a handset is that of half-duplex versus full duplex. The handset is full duplex since con-version can occur in both directions (transmit and receive) simultaneously. A speakerphone has higher gain levels in both paths and attempting to converse full duplex results in oscillatory problems due to the loop that exists within the system.
PAGE 8
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Level Detectors There are four level detectors-two on the receive side and two on the transmit side. Refer to Figure 4. The terms in parentheses from one system, and the other terms from one system. Each level detector is a high gain amplifier with back-to-bank diodes in the feedback path, resulting in non-linear gain, which permits operation over a wide dynamic range of speech levels.
PAGE 9
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Background Noise Monitors The purpose of the background noise monitors is to distinguish speech (which consists of bursts) from background noise (a relatively constant signal level). There are two background noise monitors-one for the receive path and one for the transmit path.
PAGE 10
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Attenuator Control Block Input C1 Tx Tx Rx Rx Tx Tx Rx Rx C2 Tx Rx Tx Rx Tx Rx Tx Rx C3 1 Y Y X 0 0 0 X C4 X Y y 1 X 0 0 0 Output Mode Transmit Fast Idle Fast Idle Receive Slow Idle Slow Idle Slow Idle Slow Idle X=Don’t Care; y=C3 and C4 are not both 0. A definition of the above terms: 1) ”Transmit” means the transmit attenuator is fully on (+6.0dB), and the receive attenuator is at max. Attenuation (- 46dB).
PAGE 11
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Attenuator Control Block 4) The circuit will switch to the slow idle mode when a) both talkers are quiet (no speech present), or b) when one talker’s speech level is continuously overridden by noise at the other speaker’s location. The time required to switch the circuit between transmit, receive, fast idle and slow idle is determined in part by the components at the CT pin (pin 14).
PAGE 12
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Hybrid Amplifiers The two hybrid amplifiers (at HTO+, HTO-, and HTI), in conjunction with an external transformer, provide the two-to four wire converter for interfacing to the telephone line. The gain of the first amplifier (HTI to HTO-) is set by external resistors (gain=-RHF/PHI in Figure 2), and its output drives the second amplifier, the gain of which is internally set at –1.0.
PAGE 13
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Power Supply, VB, and Chip Disable The power supply voltage at VCC (pin 4) is to be between 3.5 and 6.5V for normal operation, with reduced operation possible down to 2.8V. The power supply current is shown in Figure 18 for both the power-up and power-down mode. The output voltage at VB (pin 15) is ≈ (VCC-0.7)/2, and provides the ac ground for the system.
PAGE 14
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Design Equations Referring to Figure 10(the coupling capacitors have been omitted for simplicity), the following definitions will be used (all measurements are at 1kHz) - GMA is the gain of the microphone amplifier measured from the microphone output to TXI (typically 35V/V, or 31dB); - GTX is the gain of the transmit attenuator, measured from TXI to TXO; - GHA is the gain of hybrid amplifiers, measured from TXO to the HTO-/HTO+ differentia
PAGE 15
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Loop Gain The total loop gain must add up to less than zero dB to obtain a stable circuit. This can be expressed as: GMA+GTX+GHA+GST+GFO+GRX+GSA+GAC<0 (Equation 2) Using the typical numbers mentioned above, and knowing that GTX+GRX=-40dB, the required acoustic coupling can be determined: GAC<-[31+20.1+(-15)+0+(-40)+26.8]=-22.
PAGE 16
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Switching Threshold Since GHA is the differential gain of the hybrid amplifiers, it is divided by two to obtain the voltage V2 applied to R2. Comparator C2 switches when I4=I2.
PAGE 17
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Switching Threshold (Continue) Helps determine the minimum slope of that line. Using the component values in Equation 13 yields a GAC-MAX of –37dB. Experience has shown, however, that an acoustic coupling loss of >40dB is desirable.
PAGE 18
TS34118CS28 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) Transmit / Receive Detection Priority Although the TS34118 was designed to have an idle mode such that the attenuators are halfway between their full on and full off positions, the idle mode can be biased towards the transmit or the receive side. With this done, gaining control of the circuit from idle will be easier for that side towards which it is biased since that path will have less attenuation at idle.
PAGE 19
TS34118CS28 Taiwan Semiconductor PACKAGE OUTLINE DIMENSIONS (Unit: Millimeters) SOP-28 SUGGESTED PAD LAYOUT (Unit: Millimeters) MARKING DIAGRAM TS34118CS YML Y = Year Code M = Month Code for Halogen Free Product O =Jan P =Feb Q =Mar R =Apr S =May T =Jun U =Jul V =Aug W =Sep X =Oct Y =Nov Z =Dec L = Lot Code (1~9, A~Z) 19 Version: E1608
PAGE 20
TS34118CS28 Taiwan Semiconductor Notice Specifications of the products displayed herein are subject to change without notice. TSC or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. Information contained herein is intended to provide a product description only. No license, express or implied, to any intellectual property rights is granted by this document.