IL2410
APPLICATION NOTE
The application circuit illustrates the use of the IL2410 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 C
1
and resistor R
1
.
C
1
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 C
4
to provide a DC supply for
the tone ringer chip.
As this voltage exceeds the initiation voltage (V
SI
), oscillation starts.
With the components shown, the ouptut frequency chops between 512(f
h1
) and 640Hz(f
h2
) at a 10Hz(f
L
) rate.
The loudspeaker load is coupled through a 1300Ω to 8Ω ransformer.
The output coupling capacitor C
5
is required with transformer coupled loads.
When driving a piezo-ceramic transducer type load, the coupling C
5
and transformer (1300Ω:8Ω) are not required.
However, a current limiting resistor is required.
The low frequency oscillator oscillates at a rate (f
L
) controlled by an external resistor (R
2
) and capacitor (C
2
).
The frequency can be determined using the relation f
L
=1/1.289R
2
xC
2
. The high frequency oscillates at a f
H1
, f
H2
controlled by an external resistor (R
3
) and capacitor (C
3
). The frequency can be determined using the relation
f
H1
=1/1.504R
3
xC
3
, f
H2
=1/1.203R
3
xC
3
.
TRIGGERING IL2410 FROM CMOS OR TTL LOGIC
Figure 3
Figure 4
5
INTEGRAL [ INTEGRAL CORP. ]
