L6726

Manufacturer Part NumberL6726
DescriptionUNIVERSAL SPEECH CIRCUIT
ManufacturerUnisonic Technologies
L6726 datasheet
 


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UNISONIC TECHNOLOGIES CO., LTD
L6726
UNIVERSAL SPEECH
CIRCUIT
DESCRIPTION
The UTC L6726 is a mask-programmable, monolithic
integrated speech circuits for using in electronic telephones.
It is designed for using with a low impedance microphone.
Transmitting and receiving gain are regulated with line length.
Different regulation for various current feeds can be set by
external resistors. Typical current feeds as 48V 2·200Ω, 48V,
2·400Ω, and 36V, 2·500Ω, can be handled. Application
dependent parameters such as line balance, side tone level,
amplification and frequency response are set by external
components. Parameters are set independently which means
easy adaptation for various market needs.
The UTC L6726 is developed for using with CMOS-type dialer
ICs. A separate DTMF input is switched when the circuit is
muted, and an adjustable DC supply is provided for feeding an
external CMOS device.
FEATURES
*Minimum number of inexpensive external components, 5
capacitors and 11 resistors.
*Mute function for operation with DTMF-generator.
*Transmit and receive gain regulation for automatic loop loss
compensation.
*Extended current and voltage range 5~130mA, down to 2V.
*Differential microphone input for good balance to ground.
*Balanced receiver output stage.
*Short start-up time.
*Stabilized DC-supply for low current CMOS dialers and/or
electret microphones.
*DTMF-input controlled by mute.
ORDERING INFORMATION
Ordering Number
Normal
L6726-D18-T
L6726-S18-R
L6726-S18-T
www.DataSheet4U.com
www.unisonic.com.tw
Copyright © 2008 Unisonic Technologies Co., Ltd
Package
Lead Free
L6726L-D18-T
DIP-18
L6726L-S18-R
SOP-18
L6726L-S18-T
SOP-18
LINEAR INTEGRATED CIRCUIT
*Pb-free plating product number: L6726L
Packing
Tube
Tape Reel
Tube
QW-R108-015,B
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L6726 Summary of contents

  • Page 1

    ... Parameters are set independently which means easy adaptation for various market needs. The UTC L6726 is developed for using with CMOS-type dialer ICs. A separate DTMF input is switched when the circuit is muted, and an adjustable DC supply is provided for feeding an external CMOS device ...

  • Page 2

    ... TI Input of transmit amplifier. Input impedance 17kΩ±20% The positive power supply terminal for most of the circuitry inside the UTC L6726 (about 1mA current 4 +C consumption).The +C-PIN shall be connected to a decoupling capacitor of 47µF to 150µF When low, speech circuit is muted and the DTMF input is enabled ...

  • Page 3

    ... L6726 ABSOLUTE MAXIMUM RATINGS PARAMETER Line Voltage, t =2s p Line Current, Continuous Ambient Operating Temperature Storage Temperature 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. ...

  • Page 4

    ... R Load =400Ω+400Ω + E=48.5V C1= 1μF when artificial line is used 470μF when not used www.DataSheet4U.com UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 1 UTC L6726 1.Impedance to line and radio interference suppression. 2.Transmit gain and frequency response network. ...

  • Page 5

    ... L6726 FUNCTIONAL DIAGRAM(Cont.) C8 DTMF input 220nF 12 MIC R16 13 350Ω 27k DC supply OUT CMOS device MUTE 47μF Note : * Not used in test setup www.DataSheet4U.com UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com. UTC 6726 Sense input Control output 18k 910 Ω ...

  • Page 6

    ... L6726 FUNCTIONAL DESCRIPTION The gain of the transmitting and receiving amplifiers are continuously and euqually changed with the line length. The starting point for the gain regulation is externally set .The gain regulation can be cut-off externally, see table under gain regulation below. The outputs of the transmitting and receiving amplifiers have internals limitations of the output amplitudes. ...

  • Page 7

    ... L6726 FUNCTIONAL DESCRIPTION(Cont.) www.DataSheet4U.com UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw LINEAR INTEGRATED CIRCUIT QW-R108-015 ...

  • Page 8

    ... L6726 APPLICATION INFORMATION Refer to figure 6. Gain regulation (R1, R2): These resistors set the starting point for the gain-and side tone regulation. Input impedance pin 6 is about 5.5 kΩ±20%. Below are some typical values for R1 and R2, for some different supplies from telephone stations. ...

  • Page 9

    ... L6726 APPLICATION INFORMATION(Cont.) R15: This resistor is used to set the driving capability of the receiver output amplifier. Common values are 0 Ω Ω. Setting it for low driving capability results in function at lower line current. Breaking up pin 16 will give lower power consumption and total mute of the receiver when muting the circuit. Disconnecting pin 15 will of cause also give total receiver mute ...

  • Page 10

    ... L6726 APPLICATION INFORMATION(Cont.) www.DataSheet4U.com UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw LINEAR INTEGRATED CIRCUIT QW-R108-015 ...

  • Page 11

    ... L6726 APPLICATION INFORMATION(Cont.) DESIGN PROCEDURE: 1. Circuit impedance to the line. 2. DC-characteristic 3. Gain regulation. 4. Transmitter gain and frequency response. 5. Receiver gain and frequency response. 6. Side-tone. 7. Components to suppress radio interference, specially the wires up to the handset. Others: The circuit can be placed either in the telephone or in the handset. ...

  • Page 12

    ... L6726 APPLICATION INFORMATION(Cont.) +Line R10 R12 2 R11 Figure 9. Typical sidetone network 17 18 Figure11. Magnetic reciever connection 12 MIC 13 50k 50k Figure 13. Additional components for extended low current/voltage oeration Figure 15. Connection of a dynamic microphone www.DataSheet4U.com UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com. Low impedance network ...

  • Page 13

    ... L6726 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 www.DataSheet4U.com 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 ...