sl34118 System Logic Semiconductor. co., sl34118 Datasheet

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sl34118

Manufacturer Part Number
sl34118
Description
Voice Switched Speakerphone Circuit
Manufacturer
System Logic Semiconductor. co.
Datasheet
Voice Switched Speakerphone Circuit
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 60 Hz noise in
the reseive 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 SL34118 may be operated from a power supply, or it can be
powered from the telephone line, requiring typically 5.0 mA. The
SL34118 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
featurephone.
SLS
The SL34118 Voice Switched Speakerphone Circuit incorporates
Improved Attenuator Gain Range: 52 dB Between Transmit and
Receive
Low Voltage Operation for Line-Powered Applications (3.0-6.5 V)
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 Deined Function
Dial Tone Detector to Inhibit Receive Idle Mode During Dial Tone
Presence
System Logic
Semiconductor
T
A
ORDERING INFORMATION
= -25 to 70 C for all packages
PIN ASSIGNMENT
SL34118N Plastic
SL34118D SOIC
SL34118

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sl34118 Summary of contents

Page 1

... The SL34118 may be operated from a power supply can be powered from the telephone line, requiring typically 5.0 mA. The SL34118 can be interfaced directly to Tip and Ring (through a coupling ...

Page 2

... The SL34118 provides the necessary level detectors, attenuators, and switching control for a properly operating speakerphone. The detection sensitivity and timing are externally controllable. Additionally, the SL34118 provides background noise A monitors which make the circuit insensitive to room and line noise, hybrid amplifiers for interfacing to Tip and Ring, the microphone amplifier, and other associated functions ...

Page 3

... The capacitors on the four outputs should have the same value ( 10%) to prevent timing problems. Referring to Figure 8, on the receive side, one level detector (RLI1 the receive input receiving ac signal the same signal as at Tip and Ring, and SL34118 , the B T voltage T the second ...

Page 4

... SL34118 the other (RLI2 the output of the speaker amplifier. On the transmit side, one level detector (TLI2 the output of the microphone amplifier, while the other (TLI1 the hybrid output. Outputs RLO1 and TLO1 feed a comparator, the output of which goes to the Attenuator Control Block. Likewise, outputs RLO2 and TLO2 feed a second comparator which also goes to the Attenuator Control Block ...

Page 5

... To switch to idle slowly (slow idle), the current sources are turned off, the switch at the 2.0 k resistor is open, and the capacitor discharges to V through the external resistor R B constant = SL34118 pin (Pin 14 typically 5 turned turned on (I ...

Page 6

... SL34118 Figure 4. CT Attenuator Control Block Circuit MICROPHONE AMPLIFIER The microphone amplifier (Pin 10, 11) has the noninverting input internally connected to V the inverting input and the output are pinned out. Unlike most op-amps, the amplifier has an all-NPN output stage, which maximizes phase margin and gain-bandwidth ...

Page 7

... The input impedance typically CHIP has a threshold of 1.5 volts, and the voltage at this pin must be kept within the range of ground and not used, the pin should be grounded. Description SL34118 - 0.7)/2, and CC , forms a low pass filter for , ...

Page 8

... SL34118 Pin No Designation 12 MUT Mute input. A logic low (<0.8 V) sets normal operation. A logic high (>2.0 V) mutes the microphone amplifier without affecting the rest of the circuit. Input impedance is nominally VLC Volume control input. When VLC = V when in the receive mode. When VLC = 0.3 V Does not affect the transmit mode. ...

Page 9

... Rx Mode, RXI=150 mVrms Mode, RXI=150 mVrms (V =3 Gain Change -V =3.5 V versus AGC Gain Change - V =2 versus V =5 Idle Mode, RXI=150mVrms Range ( Mode) Rx Mode, 0.3V <V < SL34118 Min Max Unit 3.5 6 500 350 mVrms 2 1 ...

Page 10

... SL34118 ELECTRICAL CHARACTERISTICS Symbol Parameter V RXO DC Voltage RXO V RXO High Voltage RXOH V RXO Low Voltage RXOL R RXI Input Resistance RXI G Trasmit Attenuator Gain =1.0 KHz) TXI * G TXI V TXO DC Voltage TXO V TXO High Voltage TXOH V TXO Low Voltage TXOL R TXI Input Resistance ...

Page 11

... I =5.0 mA -1.0 V OUT HTI B Ratio of Current at RLI1 + RLI2 to 0 TLI1 + TLI2 to switch from 220 K from 112 SL34118 Guaranteed Limits Unit Max - 375 562 mV 1 ...

Page 12

... SL34118 EXPANDED LOGIC DIAGRAM System Logic SLS Semiconductor ...

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