LUCL9219AAR-D AGERE [Agere Systems], LUCL9219AAR-D Datasheet - Page 21

• Manufacturer Part Number: LUCL9219AAR-D
• Description: Low-Cost Line Interface with Reverse Battery and Dual Current Limit
• Manufacturer: AGERE [Agere Systems]

Data Sheet
November 2001
Agere Systems Inc.
Applications
dc Applications
Ring Trip Detection
The ring trip circuit is a comparator that has a special input section optimized for this application. The equivalent
circuit is shown in Figure 15, along with its use in an application using unbalanced, battery-backed ringing.
Ring trip detection threshold is given by the following equation:
Longitudinal Balance
The SLIC is graded to certain longitudinal balance specifications. The numbers are guaranteed by testing (Figure
5 and Figure 8). However, for specific applications, the longitudinal balance may also be determined by termination
impedance, protection resistance, and especially by the mismatch between protection resistors at tip and ring. This
can be illustrated by the following equation:
where:
LB: longitudinal balance
RP: protection resistor value in
ZT: magnitude of the termination impedance in
The
longitudinal balance specification on a specific code.
Now with
Be aware that ZT may vary with frequency for complex impedance applications.
: protection resistor mismatch in
: SLIC internal tip/ring sensing mismatch
can be calculated using the above equation with these exceptions:
available, the equation will predict the actual longitudinal balance for RP, ZT, and .
(continued)
(continued)
Figure 15. Ring Trip Equivalent Circuit and Equivalent Application
I
TH
(mA) =
V
RC PHONE
HOOK SWITCH
BAT
PHONE
V
RING
------------------------------------------------------------------------------------------------------------------------------------------------------------------------ -
LB = 20 x log
RTSN M
R
LOOP
R
402
S
3.32 M
2.94 M
510
R
+
R
------------------------------------------------------------------------------------------ -
368
TSN
0.015 RTSP M
TSP
3.40 M
368 RP
RTSN M
+
2
–
C
0.015 F
with Reverse Battery and Dual Current Limit
RTS1
ZT 2
R
R
TSN
TSP
–
+
368 ZT RP
0.015
+
–
I
15 k
P
+
RP
= I
I
N
N
L9219A/G Low-Cost Line Interface
–
+
–
V
R
BAT
S
+
8.6 V
0, ZT = 600
–
NSTAT
8.6
1000
RP = 100
and the
2799 (F)
21