MH88636-4 Data Sheet

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MH88636-4

Central Office Interface Circuit
Preliminary Information
zFeatures
•
•
•
•
•
•
•
•
•
ISSUE 2
Loop Start Trunk Interface
900Ω Input Impedance
2-4 Wire Conversion
On-Hook Reception
Line State Detection Outputs:
- Forward Loop
- Reverse Loop
- Switch Hook
- Ringing Voltage
Relay Driver
Industrial Temperature Range option
DIL and SMT versions
Meets FCC part 68 Leakage Current
Requirements
Interface to Central Office for:
• PABX
• Key Telephone Systems
• Channel Bank
• Voice Mail
• Terminal Equipment
• Digital Loop Carrier
• Optical Multiplexer
FL
RL
SHK
Ordering Information
MH88636AD-4I
28 Pin DIL Package
-40°C to 85°C
MH88636AD-4
28 Pin DIL Package
MH88636AS-4
28 Pin SMT Package
0°C to 70°C
Description
The Mitel MH88636-4 Central Office Trunk Interface
circuit provides a complete analog and signalling link
between audio switching equipment and a subscriber
Line.
The device is fabricated as a thick film hybrid
technology for optimum circuit design and very high
reliability for both commercial and industrial
temperature changes.
Applications
RV
January 1997
XLA XLB XLC XLD
VCC
VEE
AGND
Status
Detection
Line
Termination
&
Impedance
Matching
TIP
RING
2 - 4 Wire
Hybrid
Receive
Gain
Transmit
Gain
LRC
LRD
Loop Relay
Driver
RX
TX
Network
Balance
VRLY
Figure 1 - Functional Block Diagram
2-287
MH88636-4
Preliminary Information
XLB
XLC
IC
1
2
3
28
XLD
27
XLA
26
LRD
TIP
RING
IC
IC
IC
4
5
6
7
8
9
25
24
VRLY
23
22
21
AGND
20
19
SHK
RX
IC
IC
IC
IC
10
11
RL
12
FL
13
18
17
16
RV
14
15
VCC
VEE
LRC
IC
TX
IC
Figure 2 - Pin Connections
Pin Description
Pin #
Name
Description
1
XLB
Loop Relay Contact B. Connects to XLA through the Loop Relay contacts (K1) when the
relay is activated.
2
XLC
Loop Relay Contact C. Connects to XLD through the Loop Relay contacts (K1) when the
relay is activated.
3
IC
Internal Connection. No connection should be made to this pin.
4
TIP
Tip lead. Connects to the Tip lead of a Telephone Line.
5
RING
6 - 11
IC
Internal Connection. No connection should be made to this pin.
12
RL
Reverse Loop detect. In the on-hook status, a logic 0 output indicates that reverse loop
battery is present. In the off-hook state, a logic 0 output indicates that reverse loop current
is present.
13
FL
Forward Loop Detect. In the on-hook status, a logic 0 output indicates that forward loop
battery is present. In the off-hook state, a logic 0 output indicates that forward loop current
is present.
14
RV
Ringing Voltage Detect (Output). A logic 0 indicates that ringing voltage is across the Tip
and Ring leads.
15, 16,
19
IC
Internal Connection. No connection should be made to this pin.
17
TX
Transmit (Output). 4 Wire ground (AGND) referenced analog output.
18
RX
Receive (Input). 4 Wire ground (AGND) referenced analog input.
20
SHK
Switch Hook (Output). A logic 0 indicates the presence of forward or reverse battery
when LRC is logic 0 and the presence of forward or reverse loop current when LRC is logic
1.
21
LRC
Loop Relay Control (Input). A logic 1 activates the Loop Relay Driver output (LRD).
22
VEE
Negative Power Supply. -5V DC
23
AGND
24
VCC
Positive Power Supply. +5V DC
25
VRLY
Relay Supply Voltage. Typically +5V. Connects to the relay supply voltage.
2-288
Ring Lead. Connects to the Ring lead of a Telephone Line.
Analogue Ground. 4 Wire ground. Normally connected to System Ground.
MH88636-4
Preliminary Information
Pin Description (continued)
26
LRD
Loop Relay Drive (Output). Connects to the Loop Relay coil. When LRC is at a logic 1 an
open collector output at LRD sinks current and energizes the relay.
27
XLA
Loop Relay Contact A. Connects to XLB through the Loop Relay (K1) contacts when the
relay is activated.
28
XLD
Loop Relay Contact D. Connects to XLC through the Loop Relay (K1) contacts when the
relay is activated.
Functional Description
The MH88636-4 is a Central Office Interface Circuit
(COIC). It is used to correctly terminate a Central
Office 2-Wire telephone line. The device provides a
signalling link and a 2-4 Wire line interface between
the telephone line and subscriber equipment. The
subscriber equipment can include Private Branch
Exchanges (PBX's),
Key Telephone Systems,
Terminal Equipment, Digital Loop Carriers and
Wireless Local Loops.
All descriptions assume that the device is connected
as in the application circuit shown in Figure 3.
termination across Tip and Ring. The device can be
considered to be in an off-hook state and DC loop
current will flow. The line termination consists of a
DC resistance and an AC impedance.
When LRC is at a logic 0, the Line Termination is
removed from across Tip and Ring. An external
Dummy Ringer should be permanently connected
across Tip and Ring and under these conditions is
the only load on the line. The device can be
considered to be in an on-hook state and negligible
DC current will flow. The Dummy Ringer is a series
AC load of typically (17kΩ+330nF) which represents
a mechanical telephone ringer and allows ringing
voltages to be sensed. This load can be considered
negligible when the line has been terminated.
Isolation Barrier
The MH88636-4 provides an isolation barrier which
is designed to meet FCC Part 68 (November 1987)
Leakage Current Requirements.
External Protection Circuit
An external Protection Circuit assists in preventing
damage to the device and the subscriber equipment,
due to over-voltage conditions. The type of
protection required is dependant upon the
application and regulatorary standards. In Figure 3
the protection is shown in block form. Further details
should be obtained from the specific country’s
regulatorary body.
Suitable Markets
The MH88636-4 has a selectable Input Impedance
of 900Ω or 900Ω + 2.16µF. This makes it suitable
primarily for North America or Brazilian markets.
Line Termination
When LRC is at a logic 1, LRD will sink current
which energizes the Loop Relay (K1), connecting
XLA to XLB and XLC to XLD. This places a line
Depending on the Network Protocol being used the
line termination can seize the line for an outgoing
call, terminate an incoming call, or if applied and
disconnected at the correct rate can be used to
generate dial pulse signals.
The DC line termination circuitry provides the line
with an active DC load which is equivalent to a DC
resistance of less than 300Ω, dependant upon the
loop current.
Ringing Equivalent Number
The Ringing Equivalent Number (REN) is application
specific.
See the governing regulatory body
specification for details.
AC Input Impedance
The Input Impedance (Zin) is the AC impedance that
the MH88636-4 places across Tip and Ring in order
to terminate the telephone line. It can be set to
either 900Ω or 900Ω + 2.16uF by connecting an
external impedance between XLA and XLD (Zext).
To select a 900Ω Input Impedance, 1000Ω must be
connected across XLA and XLD.
2-289
MH88636-4
To select a 900Ω + 2.16µF Input Impedance, 1000Ω
+ 360Ω//2.2uF must be connected across XLA and
XLD.
Preliminary Information
system controller. The supervisory circuitry is
capable of detecting: Ringing Voltage; Forward and
Reverse loop battery; Forward and Reverse loop
current; and Switch Hook.
All connections should be kept as short as possible.
Network Balance Impedance
The MH88636-4’s Network Balance Impedance has
been optimised for either of the two Input
Impedances.
• Ringing Voltage Detect Output (RV)
The RV output provides a logic 0 when ringing
voltage is detected across Tip and Ring. It toggles at
the ringing frequency, typically going low 50ms after
the ringing voltage is applied and remains low for 50
ms after ringing voltage is removed.
•
2-4 Wire Conversion
The device converts the balanced 2-Wire input,
presented by the line at Tip and Ring, to a ground
referenced signal at TX. This circuit operates with or
without loop current; signal reception with no loop
current is required for on-hook reception enabling the
detection of Caller Line Identification (CLI) signals.
Conversely the device converts the ground
referenced signal input at RX, to a balanced 2-Wire
signal across Tip and Ring.
The 4-Wire side (TX and RX) can be interfaced to a
filter/codec, such as the Mitel MT896X, for use in
digital voice switched systems
Forward Loop and Reverse Loop Detect
Outputs (FL & RL)
The FL output provides a logic 0 when either forward
loop battery or forward loop current is detected, that
is the Ring pin voltage is negative with respect to Tip
pin voltage.
The RL output provides a logic 0 when either reverse
loop battery or reverse loop current is detected, that
is the Tip pin voltage is negative with respect to Ring
pin voltage.
• The Switch Hook Detect (SHK)
The SHK output is active if either forward loop or
reverse loop current is detected, or if forward or
reverse battery voltage is detected.
Control InputS
During full duplex transmission, the signal at Tip and
Ring consists of both the signal from the device to
the line and the signal from the line to the device.
The signal input at RX, being sent to the line, must
not appear at the output TX. In order to prevent this,
the device has an internal cancellation circuit. The
measure of attenuation is Transhybrid Loss (THL).
Transmit and Receive Gain
The Transmit Gain of the device is the gain from the
balanced signal across Tip and Ring to the ground
referenced signal at TX. It is set at 0dB.
The Receive Gain of the device is the gain from the
ground referenced signal at RX to the balanced
signal across Tip and Ring. It is set at -2dB.
Supervision Features
Line Status Detection Outputs
The MH88636-4 supervisory circuitry provides the
signalling status outputs which are monitored by the
2-290
The MH88636-4 accepts a control signal from the
system controller at the Loop Relay Control input
(LRC). This energises the relay drive output Loop
Relay Drive (LRD). The output is active low and has
an internal clamp diode to VRLY.
The intended use of this relay driver is to add and
remove the Line Termination from across Tip and
Ring, as shown in Figure 3.
If this Control input and the Supervisory Features are
used as indicated in Figure 3, Loop-Start Signalling
can be implemented.
Mechanical Data
See Figure 9 and 10 for details of the mechanical
specification.
MH88636-4
Preliminary Information
MH88636-4
+5V
4
Tip
Protection
Circuit
TIP
VCC
Dummy
Ringer
5
Ring
TX
26
LRD
RX
25
21
Loop Relay Control
1
27
K1
Zext
LRC
NOTES:
1) K1 Electro Mechanical 2 Form A
18
14
13
XLB
FL
XLA
2 XLC
28
17
Analog Out
Analog In
VRLY
RV
K1
C1
RING
+5V
K1
24
RL
SHK
12
20
Ringing Detect
Forward Loop
Reverse Loop
Switch Hook
XLD
AGND
VEE
23
C2 22
2) Dummy Ringer is typically 17kΩ + 330nF
3) C1 and C2 are decoupling capacitors
-5V
Figure 3 - Typical LS Application Circuit
2-291
MH88636-4
Preliminary Information
Absolute Maximum Ratings*
Parameters
1
DC Supply Voltages
2
3
4
5
DC Ring Relay Voltage
Storage Temperature
Ringing Voltage
Ring Trip Current
Sym
Min
Max
Units
VCC
VEE
VRLY
-0.3
0.3
-0.3
-55
7
-7
18
+125
130
180
V
TS
VRING
ITR
V
˚C
Vrms
mArms
Comments
250ms 10% duty cycle or
500ms single shot
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Recommended Operating Conditions
Parameters
1
DC Supply Voltages
2
3
DC Ring Relay Voltage
Operating Temperature
Symbol
Min
Typ‡
Max
Units
VCC
VEE
VRLY
TOP
4.75
-4.75
-40
5.0
-5.0
5.0
25
5.25
-5.25
15
85
V
V
V
˚C
0
25
70
˚C
Comments
Industrial range
MH88636AD-4I
Commercial range
MH88636A*-4
‡ Typical figures are at 25˚C with nominally ±5V supplies and are for design use only.
DC Electrical Characteristics†
Characteristics
1
Supply Current
2
3
FL
RL
SHK
RV
4
LRD
5
LRC
6
LRC
Sym
Min
Typ‡
Max
Units
4
3
35
mA
mA
mW
V
V
IOH = 0.4mA
mA
mA
V
V
µA
µA
VOL = 0.35V
Power Consumption
Low Level Output Voltage
ICC
IEE
PC
VOL
-0.3
13
13
137
0.5
High Level Output Voltage
VOH
2.4
5.25
Sink Current, Relay to VCC
Clamp Diode Current
Low Level Input Voltage
High Level Input Voltage
High Level Input Current
Low Level Input Current
IOL
ICD
VIL
VIH
IIH
IIL
100
150
0.8
2.0
40
40
† Electrical Characteristics are over recommended operating conditions unless otherwise stated.
‡ Typical figures are at 25˚C with nominally ±5V supplies and are for design use only.
2-292
Test Conditions
IOL = 4mA
VIH = 5.0V
MH88636-4
Preliminary Information
Loop Electrical Characteristics†
Characteristics
1
2
3
4
Ringing Voltage
Ringing Frequency
Operating Loop Current
Off-Hook DC Resistance
5
Leakage Current (Tip-Ring to
AGND)
SHK & FL Threshold
Tip-Ring (On-hook)
Tip-Ring Current (Off-Hook)
SHK & RL Threshold
Tip-Ring (On-Hook)
Tip-Ring Current (Off-Hook)
6
7
Symbol
Min
RV
20
16
16
Typ‡
Max
Units
110
68
70
300
320
7
Vrms
Hz
mA
Ω
mArms
14
5
20
15
Vdc
mA
LRC = 0V
LRC= 5V
-14
-5
-20
-15
Vdc
mA
LRC= 0V
LRC = 5V
260
Test Conditions
@ 20mA
@ 16mA
@ 1000VAC
† Electrical Characteristics are over recommended operating conditions unless otherwise stated .
‡ Typical figures are at 25°C with nominal ±5V supplies and are for design aid only.
2-293
MH88636-4
Preliminary Information
AC Electrical Characteristics†
Characteristics
1
2-wire Input Impedance
2
Return Loss at 2-wire
Symbol
Zin
RL
3
4
5
6
Longitudinal to Metallic
Balance
Metallic to Longitudinal
Balance
Transhybrid Loss
Gain (voltage) 2 wire to TX
THL
Relative Gains
7
11
12
13
14
15
20
Typ‡
Max
900
Ω
30
dB
58
58
53
51
dB
dB
dB
dB
60
40
20
dB
dB
dB
-0.25
-0.15
-0.25
0
0
0
+0.25
+0.15
+0.15
dB
dB
dB
-2.25
-0.15
-0.25
-2
0
0
10
5
-1.75
+0.15
+0.15
dB
dB
dB
kΩ
Ω
Input impedance at RX
Output impedance at TX
Signal Overload Level
at 2-wire
at TX
Total Harmonic Distortion
at 2-wire
at TX
Idle Channel Noise
at 2-Wire
at TX
Power Supply Rejection Ratio
at 2-wire and TX
VCC
VEE
CMRR
On-Hook Gain, 2-Wire to TX
Relative to Off-Hook Gain
3.0
0
dBm
dBm
Test Conditions
Programmed with
ZEXT=1kΩ
Test circuit as Fig 6
200-3400 Hz
Zin = 900Ω
Test circuit as Fig 7
200Hz
1000Hz
2000Hz
3000Hz-4000Hz
Test circuit as Fig 8
200Hz - 1kHz
1kHz - 4kHz
200-4000Hz
Test circuit as Fig 4
1000Hz
300Hz
3400Hz
Test circuit as Fig 5
1000Hz
300Hz
3400Hz
% THD < 5%
Ref 900Ω @ 20mA
THD
0.1
0.1
1.0
1.0
%
%
11
13
16
16
dBrnC
dBrnC
Input 0.5V, 1kHz @ Rx
Input 0.5V, 1kHz @
Tip-Ring
NC
PSRR
Ripple 0.1V, 1kHz
25
25
50
40
-1
dB
dB
dB
dB
0
1
† Electrical Characteristics are over recommended operating conditions unless otherwise stated .
‡ Typical figures are at 25°C with nominal ±5V supplies and are for design aid only.
2-294
Units
Gain (voltage) RX to 2 wire
Relative Gains
8
9
10
Min
dB
Test circuit as Fig 7
50Hz - 200Hz
200Hz - 4kHz
Input 1000Hz @ 0.5V
MH88636-4
Preliminary Information
+5V
-5V
VCC
VEE
-V
10H 300Ω
XLA
100uF
XLB
RING
I = 25mA
+
XLC
17kΩ
XLD
~
Vs = 0.5V
600Ω
330nF
100uF
TX
TIP
+
RX
AGND
10H 300Ω
Gain = 20 * Log (Vtx/Vs)
Figure 4 - 2-4 Wire Gain Test Circuit
+5V
-5V
VCC
VEE
-V
10H 300Ω
XLA
100uF
I = 25mA
XLB
RING
+
XLC
XLD
17kΩ
Z = 600Ω
330nF
100uF
TX
TIP
RX
+
Vs = 0.5V
~
AGND
10H 300Ω
Gain = 20 * Log (Vz/Vs)
Figure 5 - 4-2 Wire Gain Test Circuit
2-295
MH88636-4
Preliminary Information
-V
+5V
-5V
VCC
VEE
10H 300Ω
XLA
100uF
I = 25mA
XLB
RING
600Ω
+
XLC
368Ω
XLD
Vs = 0.5V
17kΩ
V1
368Ω
~
330nF
100uF
TX
TIP
RX
+
AGND
10H 300Ω
Return Loss = 20 * Log (V1\Vs)
Figure 6 - Return Loss Test Circuit
+5V
-5V
VCC
VEE
-V
10H 300Ω
XLA
100uF
XLB
RING I = 25mA
+
XLC
368Ω
XLD
17kΩ
V1
Vs = 0.5V
368Ω
330nF
100uF
TX
TIP
RX
AGND
+
10H 300Ω
Long to Met Bal. = 20 * Log (V1\Vs)
CMRR = 20 * Log (Vtx\Vs) - (2-4W Gain)
Figure 7 - Longitudinal to Metallic Balance and CMRR Test Circuit
2-296
~
MH88636-4
Preliminary Information
+5V
-5V
VCC
VEE
-V
10H 300Ω
XLA
100uF
XLB
RING I = 25mA
+
368Ω
XLC
XLD
Vs = 0.5V
17kΩ
~
510Ω
V1
330nF
100uF
TX
TIP
RX
368Ω
+
AGND
10H 300Ω
Met to Long Bal. = 20 * Log (V1\Vs)
Figure 8 - Metallic to Longitudinal Balance Test Circuit
0.26 Max
(6.6 Max)
0.260 +0.015
(6.6 +0.4)
0.08 Typ (2 Typ)
0.90 Typ*
(22.9 Typ)
* 0.100 +0.010
(2.54 +0.25)
0.95 Max
(24.2 Max)
0.020 +0.005
(0.5 +0.12)
*0.05 Typ
(1.27 Typ)
1.42 Max
(36.1 Max)
Notes:
1) Not to scale
2) Dimensions in inches.
(Dimensions in millimetres)
3) Pin tolerances are non-accumulative.
4) Recommended soldering conditions:
Max wave solkder temp: 260˚C for 10 secs.
* Dimensions to centre of pin.
1
Figure 9 - DIL Package Mechanical Data
2-297
MH88636-4
Preliminary Information
0.32 Max
(8.13 Max)
0.89 Typ
(22.6 Typ)
0.125 +0.015
(3.18 +0.38)
0.020 +0.005
(0.51 +0.13)
*0.05 Typ
(1.27 Typ)
* 0.100 +0.010
(2.54 +0.25)
0.060 Typ
(1.52 Typ)
Notes:
1.01 Typ
(29.5 Max)
1) Not to scale
2) Dimensions in inches.
(Dimensions in millimetres)
1
3) Pin tolerances are non-accumulative.
4) Recommended soldering conditions:
Max reflow temp: 235˚C for 10 secs.
* Dimensions to centre of pin.
1.42 Max
(36.1 Max)
Figure 10 - SMT Package Mechanical Data
0.10 (2.54)
0.10
(2.54)
Notes:
1) Not to scale
2) Dimensions in inches.
(Dimensions in millimetres)
3) All dimensions are Typical
0.89
(22.6)
0.04 (1.02)
0.06 (1.52)
Figure 11 - SMT Footprint
2-298
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TECHNICAL DOCUMENTATION - NOT FOR RESALE