SL2418 Telephone Tone Ringer with Bridge Diode The SL2418 is a monolithic integrated circuit telephone tone ringer with bridge diode, when coupled with an appropriate transducer, it replaces the electro-mechanical bell. The device is designed for use with either a piezo transducer or an inexpensive transformer coupled speaker to produce a pleasing tone composed of a high frequency (fR) alternating with a low frequency (fL) resulting in a warble frequency. The supply voltage is obtained from the AC ring signal and the circuit is designed so that noise on the line or variation of the ringing signal can not affect correct operation of the device. • On chip high voltage full wave diode bridge rectifier • Low current consumption, in order to allow the parallel operation of the 4 devices • Low external component count • Tone and switching frequencies adjustable by external components • High noise immunity due to built-in voltage-current hysteresis • Activation voltage adjustable • Internal zener diodes to protect against over voltages • Ringer impedance adjustable with external components BLOCK DIAGRAM SLS System Logic Semiconductor ORDERING INFORMATION SL2418N Plastic SL2418D SOIC TA = -20° to 70° C for package PIN ASSIGNMENT SL2418 MAXIMUM RATINGS * (TA = 25°C) Symbol Parameter Value Unit VTP Calling Voltage (f = 50 Hz) Continuous 120 Vrms VTP Calling Voltage (f = 50 Hz) 5 Sec ON/10 Sec OFF 200 Vrms ICC Supply Current 22 mA -65 to +150 °C Tstg Storage and Junction Temperature * Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recommended Operating Conditions. RECOMMENDED OPERATING CONDITIONS Symbol Parameter VCC Supply Voltage TA Operating Temperature Min -20 Max Unit 26 V +70 °C This device contains protection circuitry to guard against damage due to high static voltages or electric fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated voltages to this high-impedance circuit. For proper operation, VIN and VOUT should be constrained to the range GND≤(VIN or VOUT)≤VCC. Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or VCC). Unused outputs must be left open. ELECTRICAL CHARACTERISTICS (TA = 25°C) Guaranteed Limits Symbol Parameter Test Conditions Unit Min ICC Current Consumption without Load VON Activiation Voltage VONR Activiation Voltage Range VSUS Sustaining Voltage RD VS=8.8 to 26 V RA = 1 KΩ Differential Resistance in Off Condition VOUT Output Voltage Swing IOUT Short Circuit Current Typ 1.8 mA 12.2 13 V 8 10 V 8 8.8 V 6.4 VS = 26 V Max KΩ VCC-3 V 35 mA SLS System Logic Semiconductor SL2418 AC CHARACTERISTICS Guaranteed Limits Symbol Parameter Test Conditions Unit Min fH1 fH2 fL Output Frequencies fH1 fH2 VCC = 26 V, R1 = 14 KΩ VCC = 0 V VCC = 6 V fH1 Range R1 = 27 KΩ to 1.7 KΩ Sweep Frequency R1 = 14 KΩ, C1 = 100 nF Typ Max 2300 1700 0.1 Hz Hz 15 10 KHz Hz TEST AND APPLICATION CIRCUIT f1 = 3.22 •104 / R1 (KΩ); f2 = 5/7 f1; fsweep = 1000 / C1(nF) DESCRIPTION The SL2418 tone ringer derives its power supply by rectifying the AC ringing signal. It uses this power to activate two tone generators. The two tone frequencies generated are switched by 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 device can drive either directly a piezo ceramic converter (buzzer) or small loudspeaker. In case of using a loud-speaker, a transformer is needed. An internal shunt voltage regulator provides DC voltage to the output stage, low frequency oscillator, and high frequency oscillator. To protect the IC from telephone line transients, a zener Diode is included. SLS System Logic Semiconductor