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STLC30R81

GDK/AL detectors are active. DC line loop current is limited at 15mA (not programmable). DC characteristic is

shown in Fig.1. The line feeding voltage in On-Hook is typically 42V @ VBAT2 = -74V.

Figure 1. Characteristic in StBy Mode

Active - NP (normal polarity) or RP (reverse polarity)

the voltage drop in on-hook condition is 7.8V. Concerning AC characteristic the STLC30R81 allows to set 2Wire

termination impedance by means of external scaled impedance.

In ACTIVE mode the SLIC can perform battery reversal in a soft way, with programmable transition time, without

affecting the AC signal transmission. It is possible to program, by means of an external resistor RLIM, the value

of the current limitation in a range of 20 to 45mA. During On/Off-Hook transition, the SLIC line drivers limit the

transient current at Ilim +13mA.

Figure 2. DC Characteristic in Active mode

Active - ON-Hook transmission

This mode is selected to allow caller ID transmission in On-Hook line condition. The line feeding voltage in On-

High Impedance feeding

As in Stand-By, this mode is set in On-Hook condition, with further reduced power consumption. Higher power

efficiency turns back to a lower immunity of the Off-Hook detector to line common mode currents. The DC feed-

ing shows a constant current characteristic (Ilim = 18mA) followed by a resistive range with an equivalent series

resistance Rfeed = 1600

Thermal protection circuit is still active, preventing the junction temperature, in case of fault condition, to exceed

150°C. In High Impedance Feeding most of the circuit is switched off, only the circuit, dedicated to Off-Hook

detection, is powered. This allows reducing the total power consumption in On-hook to 30mW (typical).

15mA

D03TL590

42V

I

V

20mA ~ 45mA

D03TL591

IL

VL