stlc3075 STMicroelectronics, stlc3075 Datasheet - Page 9

• Manufacturer Part Number: stlc3075
• Description: Integrated Pots Interface For Home Access Gateway And Wll
• Manufacturer: STMicroelectronics

STLC3075
3.2.3
Active
DC characteristics & supervision
When this mode is selected the STLC3075 provides both DC feeding and AC transmission.
The STLC3075 feeds the line with a constant current fixed by RLIM (20mA to 40mA range).
The on-hook voltage is typically 40V allowing on-hook transmission; the self generated Vbat
is -50V typical.
If the loop resistance is very high and the line current cannot reach the programmed
constant current feed value, the STLC3075 behaves like a 40V voltage source with a series
impedance equal to the protection resistors 2xRp (typ. 2x50 ).
DC characteristics in active mode.
The line status (on/off hook) is monitored by the SLIC’S supervision circuit. The off-hook
threshold can be programmed via the external resistor RTH in the range from 5mA to 9mA.
Independently on the programmed constant current value, the TIP and RING buffers have a
current source capability limited to 80mA typical.
Figure 4.
Moreover the power available at Vbat is controlled by the DC/DC converter that limits the
peak current drawn from the V
R
SENSE
resistor.
DC characteristics in active mode
POS
40mA)
(20 to
Ilim
IL
supply. The maximum allowed current peak is set by
10V
2Rp
Vbat (-50V)
VL
Figure 4.
Functional description
shows the typical
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