SL2411 Tone Ringer The SL2411 is a bipolar integrated circuit designed for telephone bell replacement. • Designed for Telephone Bell Replacement • Low Curent Drain • Adjustable 2-frequency Tone • Adjustable Warbling Rate • Extension Tone Ringer Modules • Alarms or Other Alerting Devices • Adjustable for Reduced Supply Initiation Current. • Built-in hysteresis prevents false triggering and rotary dial ‘Chirps’ ORDERING INFORMATION SL2411N Plastic SL2411D SOIC TA = -45° to 65° C for package LOGIC DIAGRAM PIN ASSIGNMENT PIN 1 = VCC PIN 5 = GND 1. 2. 3. 4. Output amplifier High frequency oscillator Low frequency oscillator Hysteresis regulator (Regulator circuit has built-in hysteresis to prevent false triggering and rotary dial “Chirps”) SLS System Logic Semiconductor SL2411 PIN DESCRIPTION NAME PIN VCC 1 Positive power supply. RSL 2 External resistor LFI 3 Input low frequency oscillator LF0 4 Output low frequency oscillator GND 5 Negative power supply HF0 6 High frequency oscillator output HFI 7 High frequency oscillator input OUT 8 Tone output DESCRIPTION MAXIMUM RATINGS * Symbol Parameter Value Unit VCC DC Supply Voltage (Referenced to GND) to +30.0 V PD Power Dissipation in Still Air, Plastic DIP 400 mW -65 to +150 °C Tstg Storage 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 Min Max Unit VCC DC Supply Voltage (Referenced to GND) 13.0 29.0 V TA Operating Temperature -45 +65 °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. SLS System Logic Semiconductor SL2411 ELECTRICAL CHARACTERISTICS (Voltages Referenced to GND, TA = -45 to +65°C) Guaranteed Limits Symbol Parameter Test Conditions VSI Initiation Supply Voltage (1) ISI Initiation Supply Current (1) See Figure 1 Min Typ Max Unit 16.8 21.2 V 1.4 4.2 mA VSUS Sustaining Voltage (2) See Figure 1 9.5 12.2 V ISUS Sustaining Current (2) No Load VCC=VSUS See Figure 1 0.7 2.5 mA VOH High-Level Output Voltage VCC=21V, IOH=-15mA, Pin 6=6V, Pin 7=GND 16.7 21.0 V VOL Low-Level Output Voltage VCC=21V, IOL=15mA, Pin 6=GND, Pin 7=6V - 1.8 V IIN Maximun Input Leakage Current (Pin 3) Pin 3=6V,Pin 4=GND, VCC=21V - 1.0 µA Pin 7=6V,Pin 6=GND, VCC=21V - 1.0 µA (Pin 7) fH1 High Frequency 1 R3=191KΩ,C3=6800pF 461 563 Hz fH2 High Frequency 2 R3=191KΩ,C3=6800pF 576 704 Hz fL Low Frequency R2=165KΩ,C2=0.47µF 9.0 11.0 Hz Notes: 1. Initiation supply voltage (VSI ) is the supply voltage required to start the tone ringer oscillating. 2. Sustaining voltage (VSUS) is the supply voltage required to maintain oscillation. SLS System Logic Semiconductor SL2411 CIRCUIT CURRENT-SUPPLY VOLTAGE (NO LOAD) Figure 1 SUPPLY CURRENT (NO LOAD) vs. SUPPLY VOLTAGE Figure 2 SLS System Logic Semiconductor SL2411 APPLICATION CIRCUIT Figure 3 SLS System Logic Semiconductor SL2411 APPLICATION NOTE The application circuit illustrates the use of the SL2411 devices in typical telephone or extension tone ringer application. The AC ringer signal voltage appears across the TIP and RING inputs of the circuit and is attenuated by capacitor C1 and resistor R1. C1 also provides isolation from DC voltages (48V) on the exchange line. After full wave rectification by the bridge diode, the waveform is filtered by capacitor C4 to provide a DC supply for the tone ringer chip. As this voltage exceeds the initiation voltage (VSI ), oscillation starts. With the components shown, the ouptut frequency chops between 512(fh1) and 640Hz(fh2) at a 10Hz(fL) rate. The loudspeaker load is coupled through a 1300Ω to 8Ω transformer. The output coupling capacitor C5 is required with transformer coupled loads. When driving a piezo-ceramic transducer type load, the coupling C5 and transformer (1300Ω:8Ω) are not required. However, a current limiting resistor is required. The low frequency oscillator oscillates at a rate (fL) controlled by an external resistor (R2) and capacitor (C2). The frequency can be determined using the relation fL=1/1.289R2xC2. The high frequency oscillates at a fH1, fH2 controlled by an external resistor (R3) and capacitor (C3). The frequency can be determined using the relation fH1=1/1.504R3xC3, fH2=1/1.203R3xC3. Pin 2 allows connection of an external resistor RSL, which is used to program the solpe of the supply current vs supply voltage characteristics (see Fig2), and hence the supply current up to the initiation voltage ( VSI ). This initiation voltage remains constant independent of RSL. The supply current drawn prior to triggering varies inversely with RSL, decreasing for increasing value of resistance. Thus, increasing the value of RSL will decrease the amount of AC ringing current required to trigger the device. As such, longer sucribser loops are possible since less voltage is dropped per unit length of loop wire due to the lower current level. RSL can also be used to compensated for smaller AC couplin capacitors (C5 on Fig 3) (higher impedance) to the line which can be used to alter the ringer equivalence number of a tone ringer circuit. The graph in Fig2 illustrates the variation of supply current with supply voltage. Three curves are drawn to show the variation of initiation current with RSL. Curve B( RSL=6.8KΩ) shows the I-V characteristic for the SL2411 tone ringer. Curve A is a plot with RSL<6.8KΩ and shows an increase in the current drawn up to the initiation voltageVSI . The I-V characteristic after initiation remains unchanged. Curve C illustrates the effect of increasing RSL above 6.8KΩ initiation current decreases but again current after triggering is unchanged. SLS System Logic Semiconductor