stlc30r81 STMicroelectronics, stlc30r81 Datasheet - Page 8

• Manufacturer Part Number: stlc30r81
• Description: Integrated Ringing Slic For Short Loop Applications
• Manufacturer: STMicroelectronics

STLC30R81
Figure 6. PWM signal Input vs Sinusoidal Output
GROUND START
This mode is selected when the SLIC is adopted in a system using the Ground Start feature.
In this mode, the TIP termination is set in High Impedance ( 100K
-33V @ Vbat1 (= -38V). In case RING termination is connected to GND the sinked current is limited to 35mA.
When RING is connected to GND both Off-Hook and Ground-Key detectors are set low.
TEST MODES
This device can provide three kind of tests:
1. Phone Detection
2. Short circuit
3. Loop back
Phone Detection
This test feature checks whether a phone is connected to the line.
Starting from Active Reverse Polarity status, just changing the D0 input bit, it is possible to perform the Phone
Detection function.
The MCU measures the time span of DET. Time longer then 4ms indicates that a phone is hooked up with the
line, if no phone is connected, the time span is less than 2ms.
Table 4. Phone detection - D0 variation
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D0
0
1
D1
Control Word
1
1
D2
1
1
PWM Ring
IN
D3
0
0
CODEC
Active - Reverse Polarity
High Impedance Feeding - Normal Polarity
LPF
Rxin+
Rxin-
Rg+
Rg-
Operating Mode
while the RING one is active and fixed at
OpAmp 1
OpAmp 2