L3234 STMicroelectronics, L3234 Datasheet - Page 17

• Manufacturer Part Number: L3234
• Description: HIGHLY INTEGRATED SLIC KIT TARGETED TO PABX AND KEY SYSTEM APPLICATIONS
• Manufacturer: STMicroelectronics

External components list for L3235
To set the SLIC into operation the following parameters have to be defined:
- The AC SLIC impedance at line terminals ”Zs” to which the return loss measurements is referred. It can
- The equivalent AC impedance of the line ”Zl” used for evaluation of the trans-hybrid loss performance
- The value of the two protection resistors Rp in series with the line termination.
Once, the above parameters are defined, it is possible to calculate all the external components using the
following table. The typical values has been obtained supposing: Zs = 600 ; Zl = 600 ; Rp = 50
Notes:
1) For proper operation Cf should be selected in order to verify the following conditions:
2) For protection purposes the RP resistor is usually splitted in two part R
3) ex: BD140; MJE172; MJE350.... (SOT32 or SOT82 package available also for surface mount). For low power application (reduced battery
(2/4 wire conversion). It is usually a complex impedance.
be real (typ. 600 ) or complex.
A) cf > 150nF
B) < 1/2 f
voltage) BCP53 (SOT223 surface mount package) can be used. Depending on application enviroment an heatsink could be necessary.
f
CV
RING
D1, D2
Name
SS
: Ringing signal frequency
R
Text
R
C
C
R
Z
R
C
C
CR
Z
R
C
R
R
R
C
ZB
C
; CV
LIM
AC
AS
GF
GF
AC
PC
AS
TX
VB
R
C
H
F
F
P
T
RING
DD
Suggested Value
8.4K
100nF/100V
12500 1%
12500 1%
220pF 20%
220pF 20%
4.7 F 30%
2500
2500
6.3 V 30%
1M
6.3V 20%
15K 1%
1N4007
390nF
390nF
100 F
100nF
39K
39K
51K
4.7 F
(3)
50
to 33K
20%
1%
1%
Delay Time
On-hook Off-hook
Delay Time
GK Detector
Bias Set
Ext. Current Limit. Progr.
Negative Battery
Filter
Protection Resistors
Termination Resistor
DC/AC current feedback splitting
R
2W AC Impedance programmation
AC Feedback compensation
Slic Impedance Balancing Net.
Line impedance Balancing Net.
C
DC Decoupling Tx Output
Line Rectifier
External Transistor
V
5V supply filter
P
C
BAT
insertion loss compensation
Transybrid loss Compensation
supply filter
Function
P1
and R
P2
, with R
P1
> 30 .
f1 = 300KHz
= 0.69 C
P
H
V
C
C
47 < R
C
Z
Z
Diss
= 0.69 C
BE
FE
R
AC
AS
TX
AC
AC
RAS = 25 (2R
R
LIM
C
PC
> 2W, V
> 40, I
< 0.8V @ 100mA
=
= 25 (Z
= 25 (Z
=
=
Z
H
Formula
B
6.28 fp Z
=
2
2
P
= 25 (2R
= C
F
= 25 Zl
I
< 100
LIM
39K
C
C
C
L3234 - L3235
GF
16K
220
C
564
CEO
> 100mA
S
S
1
1
1
=
Z
Z
3mA
- 2R
- 2R
39K
AC
AS
2 f1 50R
> 60V
P
P
)
load
(2)
)
f
fp
P
sp
P
)
)
1
(1)
17/26
P