LS1240A LINEAR INTEGRATED CIRCUIT ELECTRONIC TONE RINGER WITH BUILT-IN BRIDGE RECTIFIER DESCRIPTION The Contek LS1240A is a monolithic integrated circuit, designed to be as a telephone ringer . It can drive directly a piezo-ceramic converter (buzzer). The output current capacitity of Contek LS1240A is higher than Contek LS1240, For driving a dynamic loudspeaker , Contek LS1240A needs only a decoupling capacitor. FEATURES *Low current consumption, in order to allow the parallel operation of 4 devices. *Integrated rectifier bridge with zener diodes to protect against over voltage. *Little external circuitry. *Tone and switching frequencies adjustable by external components. *Integrated voltage and current hysteresis. DIP-8 TEST CIRCUIT 2.2k W 1 mF 8 V AB 5 Contek 7 Vout RL LS1240A 10 m F 1 2 3 4 C1 100nF f1= 27200 R1(k W ) f2=0.725f1 R1 14k W f ( SWEEP 750 )=C1(nF) Contek Microelectronics Co.,Ltd. CONTEK http://www.contek-ic.com E-mail:sales@contek-ic.com 1 LS1240A LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATINGS (Ta=25 PARAMETER C) SYMBOL VALUE UNIT VAB 120 Vrms VAB 200 Vrms IDC Topr Tstg Rth-amb 30 -20 ~ +70 -65 ~ +150 200 mA C C C/W Calling Voltage(f=50Hz) Continuous Calling Voltage(f=50Hz) 5s ON/10s OFF Supply Current Operating Temperature Storage Temperature Thermal Resistance Junction-Ambient ELECTRICAL CHARACTERISTICS (Ta=25 C, unless otherwise specified) PARAMETER Supply Voltage Current Consumption Without load Activation Voltage : 1240 1240A Sustaining Voltage :1240 1240A Differential Resistance in OFF Condition Output Voltage Swing Short Circuit Current SYMBOL Vs IB TEST CONDITIONS MIN Vs=9.3 to 25V Von Von VOFF 1.5 12 12 8 7.8 6.4 RD Vout 1240 1240A AC Operation Output Frequenies : 1240 1240A Fout1/Fout2 Programming Resistor Range Sweep Frequency Iout fout1 fout2 fout1 fout2 TYP UNIT 13.5 13.5 9 9.3 V V V V kW 26 1.8 Vs-5 Vs=20V,RL=0 W RL=250W Vs=26V,R1=14k W V3=0V Vs=6V V3=0V Vs=6V C1=100nF,R1=14k W V mA V 8 7.8 9 9.3 V V 1.65 1.15 1.55 1.08 1.33 8 5.25 2.53 1.9 2.53 1.9 1.43 5.6 9.75 kHz kHz kHz kHz kHz kW Hz 7.5 Contek Microelectronics Co.,Ltd. CONTEK MAX http://www.contek-ic.com E-mail:sales@contek-ic.com 2 LS1240A LINEAR INTEGRATED CIRCUIT PIN CONFIGURATIONS Contek LINE 1 8 GROUND 2 7 CAPACITOR LINE RECTIFIER SWEEP RATE CONTROL 3 CAPACITOR OUTPUT FREQUENCY 4 CONTROL RESISTOR 6 NULL 5 BUZZER APPLICATION CIRCUIT 1 mF 1 mF 2.2kW 8 2.2kW 8 5 5 CL BUZZER LINE 7 LINE Contek LS1240 7 ContekLS1240A RL=50W to 1000W Zload>1kW 10 mF 10 mF 1 2 3 1 4 C1 100nF 2 R1 14kW 3 4 C1 100nF R1 14kW No current limitation is provided on the output stage of Contek LS1240A ,so a minimum load DC of 50 ohms is adviced. The two tone frequencies generated are switched by an internal oscillator in a fast sequence and made audible across an output amplifier in the loudspeaker, both tone frequencies and the switching frequency can be externally adjusted.The signal and the circuit is designed so that noise on the lin or variations of the ringing signal cannot affect correct operation of the device. Contek Microelectronics Co.,Ltd. CONTEK http://www.contek-ic.com E-mail:sales@contek-ic.com 3