le9502 Zarlink Semiconductor, le9502 Datasheet - Page 9

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

Note:
* denotes external components.
Fault Detection
Each channel of the Le9502 RSLIC device has a fault detection pin, F
current fault or foreign voltage fault occurs. When not in Disconnect state, there are three conditions that will cause the F
indicate a fault condition:
•
•
•
In the Disconnect state, fault detection is not supported.
Signal Conditioning
The DET
components.
If the Le9502 RSLIC device is in Low Power Standby or Normal Active modes, the DET
condition. The following equation will set the off-hook threshold:
where I
page
If the SLIC device is in the Ringing state, the DET
is set with an external resistor, R
select the value of R
where
For Legerity’s application, the ring trip current threshold is 74.6 mA which results in a R
transient filter to debounce the output ring trip signal at the DET
Circuit
The RDC
V
|I
In Normal Active and Standby state, a foreign voltage fault occurs in which V
In Reverse Polarity state, a foreign voltage fault occurs in which V
AB
20. This value produces a nominal off-hook threshold of 10.3 mA.
A
offhook_threshold
− I
on page
i
i
B
outputs are used for both off-hook and ring trip detection. The threshold for each of these functions is set by external
pin is used to set the DC feed current limit, as described in
| > I
R
L
LONG
*
20.
R
R
I
TRIP
L
F
F
*
*
is a user-chosen off-hook current threshold. R
, the following equation is used:
B
A
i
i
TRIP
V
RING PK
, from the RTRIP
R
R
S
S
Figure 7.
+
10 V(overhead voltage)
Sense
R
K
i
TRIP
output will indicate the ring trip condition. The threshold for ring trip detection
v
Zarlink Semiconductor Inc.
R
SET
Transmission Block Diagram
i
=
to VREG
500
--------------------------------------------------------------- -
=
CFILT
------------------------------------------ -
I
•
offhook_threshold
I
(
i
500 V
trip_threshold
V
9
pin. The value for C
RING PK
i
i
pins. The ring trip threshold is set on a per-channel basis. To
≈
•
C
V
HPi
REG
REF
SET
DC Feed
B
*
+
VHP
1
is above ground or V
10 V
,
is 68.1 k
or F
i
)
2
. These pins are driven low when a longitudinal
R
on page
A
IMTi
Ω
is above ground or V
TRIP
as specified in the
*
TRIP
VOUT
is nominally 47 nF as in the
i
4.
output is used to indicate an off-hook
value of 536 k
A
i
is close to V
Application Circuit
B
is close to V
Ω
REG
. C
TRIP
.
Application
is used as a
VINP
VINM
REG
i
.
pin to
i
i
on