ZL49200
Dual Channel SLIC
Data Sheet
December 2005
Features
•
•
•
•
•
•
•
Transformerless 2 W to 4 W conversion
Controls battery feed to line
Off-hook and dial pulse detection
Ring ground over-current protection
Programmable constant current feed
-30 V to -72 V battery operation
Relay and line driver electronics on board
Ordering Information
ZL49200MDC 38 Pin SIL
-40°C to +85°C
Trays
Description
The Zarlink ZL49200 Dual SLIC hybrid provides an
interface between a switching system and a subscriber
loop with 600
Ω
impedance. The functions provided by
each SLIC include battery feed, 2 W to 4 W
conversion, off-hook and dial pulse detection. All driver
electronics are included on the hybrid in order to
minimize the number of external components required
by the user.
Loop Length determination table provided on page 9.
Applications
•
•
•
•
PABX/ONS/OPS
Key Telephone Systems
Integrated Access Devices
SOHO and Home Gateway
VBAT
VDD VEE GND
Tip Drive
Controller
TIP
RING
Over-Current
Protection circuit
Audio Gain & Network
Balance circuit
VX
VR
Line Sense
2W to 4W
Conversion & Line
Impedance
VLC
Loop Supervision
Ring Drive
Controller
RF
RV
C1
SHK
Relay
Driver
VRLY
RLYC
RLYD
5v External Electro-
mechanical relay,
DPDT/2 Form C
C7 100nF, 20%
C6 1µF, 20%, 16V
Ringing Signal
C7
C6
GND
Figure 1 - Dual Channel SLIC Single Channel Schematic Diagram
1
Zarlink Semiconductor Inc.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 2004-2005, Zarlink Semiconductor Inc. All Rights Reserved.
ZL49200
Pin Diagram
Data Sheet
RLYC
VRLY
RLYD
VDD
GND
VEE
VBAT
I/C
TIP
RING
VLC
RF
RV
I/C
GND
VX
VR
C1
SHK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
SLIC
#1
RLYC
VRLY
RLYD
VDD
GND
VEE
VBAT
I/C
TIP
RING
VLC
RF
RV
I/C
GND
VX
VR
C1
SHK
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
SLIC
#2
Power Supply Pin Out
Pin Out
#1, #2
4, 23
5, 24
15, 34
6, 25
7, 26
11, 30
2, 21
Name
VDD
GND
VEE
VBAT
VLC
VRLY
Positive supply rail.
+5 V
Ground. Return path for +5 V and -5 V.
This should also be connected back to the return
path for the loop battery, Cap and relay drive ground RLYGND.
Negative supply rail.
-5 V
Battery Voltage
for powering the line
Reference Voltage (Input).
This pin is used to set the subscribers loop constant current.
Changing the input voltage sets the current to any desired value within the working limits.
Relay voltage source.
Voltage source for relay driver.
Description
2
Zarlink Semiconductor Inc.
ZL49200
Analog I/O Pin Out
Pin Out
#1, #2
1, 20
3, 22
8, 27
9, 28
10, 29
12, 31
13, 32
14, 33
16, 35
17, 36
18, 37
19, 38
Name
RLYC
RLYD
I/C
TIP
RING
RF
RV
I/C
VX
VR
C1
SHK
Description
Relay Control (Input).
An active high on this pin will switch RLYD low.
Relay Voltage Output.
Voltage source used to drive relay coil
Internal Connection.
Tip.
Connects to the TIP lead of the telephone line.
Ring.
Connects to the RING lead of the telephone line.
Ring Feed.
Connects to the RING lead via the Ring feed resistor.
Data Sheet
Ring Voltage and Audio Feed.
Connects directly to Ring Feed via a relay.
Internal Connection.
Transmit Audio (Output).
This is the 4 W analog signal to the SLIC.
Receive Audio (Input).
This is the 4 W analog signal to the SLIC.
Filter capacitor
for ring trip, capacitor connected between this pin and GND.
Switch Hook (Output).
This pin indicates the line state of the subscribers telephone.
The output can also be used for dial pulse monitoring. SHK is high in off-hook state.
Functional Description
The ZL49200 is the analog SLIC for use in a 4 Wire switched system. The SLIC performs all of the normal interface
functions between the CODEC or switching system and the analog telephone line such as 2 W to 4 W conversion,
constant current feed, switch hook indication, ringing and ring trip detection.
2 Wire to 4 Wire Conversion
The hybrid performs 2 wire to 4 wire conversion by taking the 4 wire signal from an analog switch or voice CODEC,
a.c. coupled to VR and converting it to a 2 wire differential signal at tip and ring. The 2 wire signal applied to tip and
ring by the telephone is converted to a 4 wire signal VX which is a.c. coupled to the input of the analog switch or
voice CODEC.
3
Zarlink Semiconductor Inc.
ZL49200
Loop Supervision & Dial Pulse Detection
Data Sheet
The Loop Supervision circuit monitors the state of the phone line and when the phone goes “Off Hook” the SHK pin
goes high to indicate this state. This pin reverts to a low state when the phone goes back ‘On Hook” or if the loop
resistance is too high for the circuit to continue to support a constant current feed.
The SHK output can also be monitored for dialing information when used in dial pulse system.
Ringing and Ring Trip Detection
Ringing is applied to the line by applying a logic low to the RLYC relay control pin. When an off hook condition is
detected, SHK goes high and could be connected to RLYC input to remove ringing.
Constant Current Control
The ZL49200 could be programmed to provide constant current line feed between 18 mA to 26 mA by applying an
appropriate DC voltage to VLC input. VLC can be set between 8.75 VDC and –1.25 VDC. The relationship is
defined by the equation:
ILoop = (VBAT / 1.89 – VLC / 1.25) +/- 2 mA
e.g. for VLC =0 V, VBAT = -48 V
ILoop = 25 mA +/- 2 mA
4
Zarlink Semiconductor Inc.
ZL49200
Application Information
Most PBX applications will have line lengths less than 2 km
Most C.O.... applications will have line lengths up to 5 km
A single No 22 (AWG) cable is about 250 Ohms/km
A PBX operating loop (R
LOOP)
or ONS will normally be below 1000 Ohms, (incl.... phone).
A C.O. operating loop (R
LOOP)
or OPS could be up to 3000 Ohms (incl.... phone).
ONS therefore are normally short loops whilst OPS are normally long loops.
This affects the Battery Feed function of the SLIC.
There are various parameters that affect the battery feed requirements.
Resistance of the line
Resistance of the phone
Loop current
Feed resistor value
Line driver voltage drop
Battery voltage
R
L
R
P
I
LOOP
R
F
V
LD
V
BAT
Maximum limit that you must be capable handling
Normally fixed for a particular country
Normally fixed for a particular country
Fixed in the SLIC design
Data Sheet
Fixed by the product, usually between 8 V to 10 V depending on V
BAT
Fixed in the system
If we wish to work out what is the maximum Line resistance we can handle we can use the following formulae:
R
L
= {[-V
BAT
- V
LD
] / I
LOOP
} - [R
P
+ 2R
F
]}
Typical values of V
LD
= 10V, I
LOOP
= 15 to 30mA, R
F
= 50 to 300 Ohms and R
P
= 300 Ohms
If we set V
BAT
= -72V, I
LOOP
= 18mA,assume the phone is 300 Ohms and use a hybrid with R
F
= 220 Ohms and V
LD
=10V like the ZL49200 we get:
R
L
= {[-V
BAT
- V
LD
] / I
LOOP
} - [R
P
+ 2R
F
]
R
L
= {[72V - 10V)] / 18mA} - [300R + 2x220R]
Therefore R
L
= 2700 Ohms (or R
LOOP
= 3000 Ohms incl... phone)
Equivalent line length = (RL/2) / (250 ohm/km) = 5.4km
If we set V
BAT
= -48V, I
LOOP
= 18mA,assume the phone is 300 Ohms and use a hybrid with R
F
= 220 Ohms and V
LD
=10V like the ZL49200 we get:
R
L
= {[-V
BAT
- V
LD
] / I
LOOP
} - [R
P
+ 2R
F
]}
R
L
= { [48V - 10V] / 18mA} - [ 300R + 2x220R]
Therefore R
L
= 1371 Ohms (or R
LOOP
=1671 Ohms incl... phone)
Equivalent line length = (RL/2) / (250 ohm/km) = 2.7km
5
Zarlink Semiconductor Inc.
京公网安备 11010802033920号
EEWORLD
