SL2410 datasheet(5/6 Pages) SLS

5 / 6 page

SL2410

System Logic

Semiconductor

SLS

APPLICATION NOTE

The application circuit illustrates the use of the SL2410 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 1300

Ω to 8Ω ransformer.

The output coupling capacitor C5 is required with transformer coupled loads.

When driving a piezo-ceramic transducer type load, the coupling C5 and transformer (1300

Ω: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.

TRIGGERING SL2410 FROM CMOS OR TTL LOGIC

Figure 3

Figure 4

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