2-139
Features
ONS SLIC
Variants
- 1 Germany
- 3 UK
- 7 North America
Transformerless 2W to 4W conversion
Battery Feed to line
Off-Hook and dial pulse detection
Tip and Ring ground over-current protection
Power Denial
Integral Ringing Amplifier
Programmable Loop Current
Wide V
BAT
Operating Range
Applications
Line Interface for
PABX
Pair Gain Systems
Satellite Communication Systems
Key Telephone Systems
Marine Systems
Cordless Local Loop
Description
The Mitel MH88615 ONS SLIC provides a complete
interface between a switching system and a
subscriber loop. The functions provided by the
MH88615 include battery feed and integral ringing
amplifier feed to the subscriber line, 2W to 4W
conversion current feed, off-hook and dial pulse
detection. The device is fabricated as a thick film
hybrid in a 20 pin single-in-line package.
ISSUE 1
April 1995
Ordering Information
MH88615-1 20 Pin SIL Package
MH88615-3 20 Pin SIL Package
MH88615-7 20 Pin SIL Package
0
C to 70
C
Power Denial
Tip &
Ring
Drivers
Constant
Current Feed
Ringing Control
2-Wire to 4-Wire
Conversion
Loop
Supervision
RC
RV
VR
VX
VRef
CAP
SHK
RING
TIP
PD
VBat
DCRI
Figure 1 - Block Diagram
MH88615
ONS Subscriber Line Interface Circuit
Advance Information
2-140
MH88615
Advance Information
Figure 2 - Pin Description
Pin Description
Pin #
Name
Description
1
TIP
Tip Lead. Connects to the "Tip" lead of subscriber line.
2
RING
Ring Lead. Connects to the "Ring" lead of subsriber line.
3
NC
No Connection. This pin may be used for internal connections.
4
DCRI
DC Ringing Voltage Input. A continuous 120 Vdc is applied to this pin. This voltage is the
positive supply rail for the internal ringing amplifier for subscriber line.
5
LPGND
Battery Ground. V
Bat
return path for subscriber line. Connects to the systems's energy
dumping ground.
6
VBat
Battery Voltage. Battery supply feed for subscriber line. Typically -48Vdc is applied to this
pin.
7
NC
No Connection. This pin may be used for internal connections.
8
VDD
Positive Supply Voltage. +5V dc supply rail.
9
AGND
Analogue Ground. V
DD
and V
EE
return path.
10
VEE
Negative Supply Voltage. -5V dc supply rail.
11
RC
Ringing Control. This input enables the ringing voltage feed to Tip and Ring for subscriber
line.
12
PD
Power Denial. A logic high will isolate the battery voltage for Tip and Ring.
13
NC
No Connection. This pin may be used for internal connections.
14
SHK
Switch Hook Detect. A logic high indicates when subscriber line has gone off-hook.
15
VR
Receive Signal. This is the 4 wire analogue signal received at subscriber's set.
16
VRef
Reference Voltage. A dc reference voltage is applied to this pin to set the constant current
feed to subscriber line. This pin may also be grounded for normal 25mA loop current.
17
CAP
Ring Trip Filter Capacitor. A capacitor is normally connected from this pin to ground and
filters out low frequency ringing signals, preventing false off-hook conditions.
18
VX
Transmit Signal. This is the 4 wire analogue signal transmitted from subscriber's set.
19
NC
No Connection. This pin may be used for internal connections.
20
RV
Ringing Voltage. 1.5 Vrms signal is injected to this pin.
TIP
RING
NC
DCRI
LPGND
VBat
NC
VDD
AGND
VEE
RC
PD
NC
SHK
VR
VRef
CAP
VX
NC
RV
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Advance Information
MH88615
2-141
Functional Description
The Mitel MH88615 ONS SLIC provides a complete
interface between a switching system and a
subscriber loop. The functions provided by the
MH88615 include battery feed and integral ringing
amplifier feed to the subscriber line, 2W to 4W
conversion, constant current feed, off-hook and dial
pulse detection. The device is fabricated as a thick
film hybrid in a 20 pin single-in-line package.
The MH88615 is intended for applications where low
cost and basic functionality is important. The
MH88615 features an integral ringing amplifier which
enables a system designer to provide typically 60
Vrms ringing without having to generate a high
voltage, high current ac signal.
The SLIC uses a transformerless 2-4 wire converter
which can be connected to a CODEC to interface the
2 wire subscriber loop to a TDM (time division
multiplex) PCM (pulse code modulation) digital link.
Powering of the subscriber line is provided though
precision battery feed resistors on the hybrid. The
thick film hybrid circuit also contains control,
signalling and status circuits which combine to
provide a complete functional solution. A power
denial facility is provided which isolates the Battery
Feed from Tip and Ring.
The MH88615 is designed to meet German
regulatory approvals, UK regulatory approvals
(BS6305), and capable of meeting the approvals for
the USA (FCC Part 68/EIA 464).
Constant Current Feed
The loop current is programmed by the dc reference
voltage applied to V
Ref
.
Switch Hook Detection
When the dc current exceeds an internal threshold
level, the switch hook output (SHK) will go high. If
the loop resistance is so high that V
Bat
can no longer
supply the required loop current, the output SHK will
go low. This indicates that the loop resistance is too
high and the line is on hook.
DC Loop Current Limit
Under Tip or Ring ground conditions the loop current
is nominally limited to 42mA.
Power Denial
A logic high voltage applied to the power denial input
effectively removes the battery voltage from the loop
driver circuitry. The resulting loop current is
negligible and power consumption is minimised. The
power denial function is useful for disabling a loop
which may have a ground fault.
The SLIC is capable of detecting and indicating off-
hook and unbalanced conditions as well as inhibiting
ringing while in power denial.
Input and Network Impedance
The Input and Network Balance Impedances are
defined by the variant type on the MH88615.
MH88615-1Germany
Z
in
= 220
+ (820
//115nF)
Z
net
= 220
+(820
//115nF)
MH88615-3 UK
Z
in
= 370
+ (620
//310nF)
Z
net
= 300
+ (1000
//220nF)
MH88615-7 North America
Z
in
= 600
Z
net
= 350
(1k
//210nF)
Ringing Amplifier
The MH88615 incorporates an integral ringing
amplifier. A nominal 1.5Vrms ac signal is applied to
the RV pin and this produces a ringing signal of
typically 60 Vrms. This should ensure that the SLIC
can support a REN of 5.
Transmit Gain
Transmit gain (Tip-Ring to Vx) is fixed at 0.dB. A
dcbias on the ac input signal does not effect the
ringing signal.
Receive Gain
Receive Gain (VR to TIP-RING) is fixed at 0dB.
For correct gain, the SLIC input impedance must
match the line impedance
2-142
MH88615
Advance Information
Absolute Maximum Ratings*-
Voltages are with respect to AGND.
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Recommended Operating Conditions
* Typical figures are at 25C with nominal +5V supplied and are for design aid only.
* -48V and are for design aid only
Parameter
Symbol
Min
Max
Units
Comments
1
Supply Voltages
V
Bat
V
DD
V
EE
V
DCRI
0.3
-0.3
0.3
-0.3
65
6
-6
140
V
V
V
V
With respect LPGND
With respect LPGND
2
Storage Temperature
T
S
-55
125
C
Characteristics
Sym
Min
Typ*
Max
Units
Comments
1
Supply Voltages
V
Bat
V
DD
V
EE
V
DCRI
-20
4.75
-4.75
0
-48
5.0
-5.0
48
-60
5.25
-5.25
130
V
V
V
V
2
Operating Temperature
T
OP
0
20
70
C
3
AC Ring Generator
Voltage
Frequency
V
R
F
R
17
60
90
68
V
RMS
Hz
V
BAT
= -48V
DC Electrical Characteristics*
Characteristics
Sym
Min
Typ
Max
Units
Test Comments
1
Supply Current
I
DD
I
EE
I
Bat
10
5
2.5
mA
mA
mA
PD on
2
Power Consumption
PC
150
1700
mW
mW
Standyby
Active
3
Constant Current Line Feed
I
Loop
23
25
27
mA
V
Ref
= AGND
4
Adjustable Loop Current Range
I
Loop
18
30
mA
5
Maximum Operating Loop
Resistance
R
Loop
1200
V
Bat
=-48V @
I
Loop
=18mA,
R
Loop
=includes
telephone set
6
Ring Ground Over-Current
42
mA
7
Off-Hook Detect
Output Low Voltage
Output High Voltage
V
OL
V
OH
2.7
0.4
V
V
Active High Logic
8
Off-Hook Detect
Output Low Current
Output High Current
I
OL
I
OH
4
-400
mA
A
9
RC, PD Control Input
Input Low Voltage
Input High Voltage
V
OL
V
OH
2.0
0.7
V
V
Active High Logic
10
RC, PD Control Input
Input Low Current
Input High Voltage
I
IL
I
IH
-500
500
A
A
2-143
Advance Information
MH88615
AC Electrical Characteristics*
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Typical figures are at 25
C and are for design aid only.
Note 1: All of the above test conditions use a test source impedance which matches the device's impedance.
Note 2: THD is measured with "A Weight" filter.
AC Electrical Characteristics*- MH88615-1
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Note:
Return Loss reference impedance are defined by variant type.
Transhybrid Loss is measured when terminated with network impedance.
AC Electrical Characteristics*- MH88615-3
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Note:
Return Loss reference impedance are defined by variant type.
Transhybrid Loss is measured when terminated with network impedance.
Characteristics
Sym
Min
Typ
Max
Units
Test Comments
1
Ringing voltage
V
R
F
R
17
38
68
Vrms
Hz
Superimposed on
V
Bat
= -48V. RV=1.5
Vrms
2
Ring Trip Detect Time
100
ms
3
Input Impedance at VR
47
100
k
4
Output Impedance at Vx
10
5
Gain 2-wire to Vx
-0.25
0
0.25
dB
6
Frequency Response 2-wire to Vx
-0.15
0
0.15
dB
Relative to 1kHz
300Hz to 3.4 kHz
7
Gain Vr to 2-wire
-0.25
0
0.25
dB
8
Frequency Response Vr to 2-wire
-0.15
0
0.15
dB
Relative to 1kHz
300 Hz to 3.4 kHz
9
Total Harmonic Distortion
THD
0.5
%
10
Common Mode Rejection Ratio
CMRR
50
dB
11
Idle Channel Noise
Nc
12
dBrnC
12
Power Supply Rejection Ratio at 2-
Wire or VX
PSRR
25
dB
Ripple 0.1V
1kHz @
VDD
Characteristics
Sym
Min
Typ
Max
Units
Test Comments
1
Ringer Equivalence
REN
5
1 REN= 8000
@ 25 Hz
2
Return Loss
RL
20
24
20
dB
dB
dB
200 Hz - 500 Hz
500 Hz - 2.5 kHz
2.5kHz - 3.4 kHz
3
Transhybrid Loss
THL
24
dB
300 Hz - 3.4 kHz
4
Longitudinal to
Metallic Balance
32
54
dB
dB
50 Hz - 300 Hz
300 Hz - 4 kHz
Characteristics
Sym
Min
Typ
Max
Units
Test Comments
1
Ringer Equivalence
REN
4
4 REN= 2200
@ 25 Hz
2
Return Loss
RL
20
dB
300 Hz - 3.4 kHz
3
Transhybrid Loss
THL
20
dB
300 Hz - 3.4 kHz
4
Longitudinal to
Metallic Balance
52
dB
300 Hz - 3.4 kHz
2-144
MH88615
Advance Information
AC Electrical Characteristics*- MH88615-7
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Note:
Return Loss reference impedance are defined by variant type.
Transhybrid Loss is measured when terminated with network impedance.
Figure 3 - Mechanical Data
Characteristics
Sym
Min
Typ
Max
Units
Test Comments
1
Ringer Equivalence
REN
5
1 REN= 5000
@ 30 Hz
2
Return Loss
RL
24
dB
300 Hz - 3.4 kHz
3
Transhybrid Loss
THL
20
dB
300 Hz - 3.4 kHz
4
Longitudinal to
Metallic Balance
52
dB
300 Hz - 3.4 kHz
0.12 Max
0.010 + 0.005
(0.25 + 0.13)
0.25 Max
(6.4 Max)
Side View
*
0.05 + 0.02
(1.3 + 0.5)
*
0.05 + 0.020
(1.25 + 0.5)
0.100 + 0.010
(2.54 + 0.25)
0.180 + 0.02
(4.6 + 0.5)
2.1 Max. (106.7 Max.)
0.750 Max.
(19.0 Max.)
1 2 3
4
19 20
(0.5 + 0.13)
0.020 + 0.005
0.29 Max
(7.4 Max)
Notes:
1) Not to scale
2) Dimensions in inches).
3) (Dimensions in millimetres).
*Dimensions to centre of pin &
tolerance non accumulative.
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