STLC30R81

6/17

Figure 3. DC Characteristic in Hi-Z Feeding

RINGING

The STLC30R81 can provide three kind of signal waveform modes: Sinusoidal, trapezoidal, PWM. When this

mode is selected, the SLIC is switched to VBAT2 (-74V); both DC/AC feedback loop are disabled and the SLIC

line drivers operate as voltage buffers.

Trapezoidal Ringing Waveform

The ring waveform is obtained toggling the D2 control bit at the desired ring frequency. This bit in facts, controls

the line polarity: 0 = direct, 1 = reverse. The transition between the two polarities is performed in a "soft" way.

This means that TIP and RING wire exchange their polarities following a ramp transition (see Fig.4).

The CREV is capacitor sets the shape of the ringing trapezoidal waveform. Once ring trip is detected, the DET

output is set low and remains latched keeping the STLC30R81 in Stand-by mode until the operative mode is

modified by any Input Word.

Figure 4. Typical Ringing Waveform

* Distortion already less than 10%

Sinusoidal Ringing Waveform

The STLC30R81 has two couple of inputs: Rxin+/Rxin- and Rg+/Rg-; this means that it is possible to select two

different paths to generate the sinusoidal waveform ringing.

CREV

Crest Factor @ 20Hz

Crest Factor @ 25Hz

22nF

1.2

1.26

27nF

1.25

1.32

33nF

1.33

Not significant (*)

18mA

D03TL592

50V

I

V

3V typ

3V typ

D03TL593

GND

TYP

dV/dT

set by CREV

RING

VBAT2