le9502 Zarlink Semiconductor, le9502 Datasheet - Page 5

• Manufacturer Part Number: le9502
• Description: Ringing Subscriber Line Interface Circuit
• Manufacturer: Zarlink Semiconductor

Note:
* denotes external components.
Ringing
The Le9502 RSLIC device only provides a method for creating internal ringing. Internal ringing is accomplished by applying a
single or differential ringing waveform using the VRINGP and VRINGM pins, and placing the Le9502 RSLIC device into the
ringing state via the device's control bits. When the Le9502 RSLIC device is in the Ringing state, the gain from the Le9502 RSLIC
device's differential ringing input pin to the output, is K
waveform as shown below in
device is near -4 V, and the B
B
regulator solution, shown in the application circuit on
transistor in the switching circuit that enables the Le9502 to provide a 90 Vpk ringing signal into a lower REN load. The waveform
can be either sinusoidal or trapezoidal under the control of the codec device.
–(K
i
(RING) lead of the Le9502 RSLIC device is held near -4 V, while the A
R
• V
RING_pk
–4 V
+ 4)
I
LTH
R
DC
*
B. Voltage Output at A (TIP) (dashed line) and B (RING) (solid line) Pins
K
DC
RDC
Figure
Figure 4. DC Feed Block Diagram, Active and Standby Modes
i
F
(RING) lead is brought negative. Likewise, on the negative half cycle of the input waveform, the
i
+V
A. Voltage Applied to VRING Input (VRINGP, VRINGM)
-V
RING_pk
5). On the positive half cycle of the input waveform, the A
RING_pk
Current Mirrors
/ 2
VRINGM
VRINGP
/ 2
Polarity Control
VCC
Figure 5. Ringing Waveforms
CS1
Zarlink Semiconductor Inc.
page
R
(the ringing voltage gain). The output waveform is a quasi-balanced
C
LPF
LPFi
20, incorporates the use of a higher power PNP bipolar switching
*
I
i
LOOP
5
K
DC
Level Shift
i
(TIP) lead is brought more negative. The low cost
Sense
Sum/
i
(TIP) lead of the Le9502 RSLIC
R
R
S
S
I
A
I
B
B
A
i
i
(TIP)
(RING)
I
LOOP
R
L