L38812

UTC L388 12 LINEAR INTEGRATED CIRCUIT VOICE-SWITCH CIRCUIT FOR HANDSFREE SPEAKERPHONE TAM DESCRIPTION The UTC L388 12 contains all the necessary circuitry, amplifiers, detectors, comparators and control functions to implement a high performance, voice-switched, ”hands-free” function in an answering machine. The UTC L 388 12 is designed for answering machines that are either powered from the telephone line or from a mains powered dc. supply. Filtering of both the audio and control signals in both transmitter and receiver channels possible. An external loudspeaker amplifier has to be used, normally the same as used for the answering machine. SOP-16 DIP-18 FEATURES *Settable gain dynamics (25 or 50dB) *Low power consumption, totally 1.0mA at 3.3V typical. *Background noise compensation in the transmitting channel *with hold function. *Excellent noise performance. *Both channel input amplifiers have balanced inputs. *Minimum of external components needed for function. PIN CONFIGURATION 16-pin SO package CTR -Txin +Txin F2out Txout TxDetin TxDetout NDet 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 GND +V -Rxin F5out Rxout RxDetin RxDetout CMP F2out Txout TxDetin TxDetout N Det CMP RxDetout Rx Detin Rxout 1 2 3 4 5 6 7 8 9 18-pin DIP package 18 17 16 15 14 13 12 +Txin -Txin CTR NC GND +V -Rxin 11 +Rxin 10 F5out UTC UNISONIC TECHNOLOGIES CO. LTD 1 QW-R108-013,A UTC L388 12 PIN DESCRIPTIONS 16-pin SO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 LINEAR INTEGRATED CIRCUIT DESCRIPTION Control input for gain dynamics (25 or 50dB), mute and disable. Transmitter channel negative input. Input impedance 3kΩ. Transmitter channel positive input. Input impedance 100kΩ. Output of the second amplifier in the transmitter channel. Transmitter channel output. Min. ac load impedance 10kΩ. Input of the transmitter channel signal detector. Input impedance 13kΩ. Output of the transmitter channel signal detector. Goes negative referred to the internal ref. voltage of app.2V when a transmitter signal is present. Background noise detector output. Goes positive referred to the internal ref. Voltage of app.2V when a background noise signal is present. Comparator input.. Summing point to the different Detector outputs. Output of the receiver channel signal detector. Goes positive referred to the internal ref. Voltage of app.2V when a receiver signal is present Input of the receiver channel signal detector. Input impedance 13kΩ. Receiver channel output. Min. ac load impedance 10kΩ. Output of the second amplifier in the receiver channel. Receiver channel positive input. Input impedance 140kΩ. Receiver channel negative input,Input impedance 20kΩ. Supply of the speech switching circuitry. A shunt regulator, voltage apprx. 3.3V at 1.0mA. System ground. Not connected. 18-pin DIP 16 17 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 SYMBOL CTR -Txin +Txin F2out Txout TxDetin TxDetout NDet CMP RxDetout RxDetin Rxout F5out +Rxin -Rxin V+ GND NC BLOCK DIAGRAM(16-pin SO package) 1 5 F3 Control F6 12 16 13 11 4 6 15 + F2 F5 2 3 + - F1 8 7 9 10 Ref. 14 F4+ UTC UNISONIC TECHNOLOGIES CO. LTD 2 QW-R108-013,A UTC L388 12 MAXIMUM RATINGS PARAMETER Speech switch supply current Voltage Pin 1-14 Operating temperature Storage temperature LINEAR INTEGRATED CIRCUIT SYMBOL ID Topr Tstg RATINGS 10 -0,5 ~ Vpin15+0.5 -20 ~ +70 -55 ~ +125 UNIT mA V ℃ ℃ TEST CIRCUIT V+ + VTxout RxDetin 11 ID 100nF 15 V+ RTxout 10μF + ID 100μF/16V 15 V+ 5 Txout 6 TxDetin GND 16 10μF Rxout 12 + RxDetin 11 VRout RRout CRX 10μF + 1μF 10μF L388 12 GND RxDetout 10 16 VRef CTx F2out RF2out + 4 F2out + + VTxin L388 12 F5out 13 -Rx in + 3 +Txin RxDetout CTR 14 N 2 -Txin8Det TxDetout CMP 7 9 10 1 CTxDet 1μF 0.1μF CRxDet + + RCTR INDet VNDet ITxDet VTxDet IRxDet ICTR V+ ITxin IRxin F5out RF5out 4.7μF VRxin ISOLATION AND MEASUREMENT OF VRef VCMP VRxDet VCTR ELECTRICAL CHARACTERISTICS (Ta=25℃,f=1kHz, RCTR=0,CTxDet=0,RTxout= ∞,RRXout= ∞,RF2out= ∞, RF5out= ∞,RTX=0,RRX=0,CRxDet=0 and ID=1.0mA unless otherwise noted) PARAMETER Speech control section Terminal voltage, V+ Internal reference voltage, VRef Frequency response for all amplifiers Transmit gain, 20·Iog(VTxout/VTxin) TEST CONDITIONS ID=1.0mA MIN TYP 3.3 1.96 MAX UNIT V V dB dB dB dB dB dB dB dB dB dB dB dB dB dB 200-3400Hz,Relative 1 kHz VCMP=VRef-0.1V VCMP=VRef+0.1V VCMP=VRef-0.1V RCTR=100k,VCTR=V+ VCMP=VRef+0.1V RCTR=100k,VCTR=V+ Receive gain, 20·Iog(VRxout/VRxin) VCMP=VRef+0.1V VCMP=VRef-0.1V VCMP=VRef+0.1V RCTR=100k,VCTR=V+ VCMP=VRef-0.1V RCTR=100k,VCTR=V+ Max transmit detector gain, VTxDet