E-STLC3075 データシートの表示（PDF） - STMicroelectronics
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E-STLC3075 Datasheet PDF : 36 Pages
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Functional description
STLC3075
AC characteristics
The SLIC provides the standard SLIC transmission functions.
Once in active mode the SLIC can operate with two different Tx, Rx gains set by the gain set
control bit (See Table 7 below).
Table 7. Gain set in active mode
Gain set
4 to 2 wires gain 2 to 4 wires gain Impedance synthesis scale factor
0
0 dB
-6 dB
x 50
1
+6 dB
-12 dB
x 25
● Input impedance synthesis: can be real or complex and is set by a scaled (x 50 or
x 25) external ZAC impedance
● Transmit and receive: The AC signal present on the 2W port (TIP and RING pins) is
transferred to the Tx output with a -6 dB or -12 dB gain and from the Rx input to the 2W
port with a 0 dB or +6 dB gain
● 2 to 4 wires conversion: The balance impedance can be real or complex, the proper
cancellation is obtained by means of two external impedances ZA and ZB
Once in active mode (D1=1) the SLIC can operate in different states setting properly D0 and
D2 control bits (see also Table 8).
Table 8.
D0
SLIC states in active mode
D1
D2
Operating mode
0
1
0 Active normal polarity
0
1
1 Active reverse polarity
1
1
0 Active TTX injection (normal polarity.)
1
1
1 Active TTX injection (reverse polarity.)
Polarity reversal
The D2 bit controls the line polarity, the transition between the two polarities is performed in
a ’soft’ way. This means that the TIP and RING wires exchange their polarities following a
ramp transition (see Figure 5). The transition time is controlled by an external capacitor
CREV. This capacitor also sets the shape of the ringing trapezoidal waveform. When the
control pins set the battery reversal, the line polarity is reversed with a proper transition time
set via an external capacitor (CREV).
Figure 5. TIP/RING typical transition from direct to reverse polarity
GND
TIP
4V typ.
dV/dT set
by CREV
RING
40V typ
ON-HOOK
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