MITEL MH88620IN

MH88620IN

C.O. SLIC
Preliminary Information
Features
ISSUE 3
Ordering Information
•
600 ohm input impedance
•
Externally selectable network balances
•
Transformerless 2-4 wire conversion
•
Programmable constant resistance feed
•
Off-hook and dial pulse detection
•
High immunity to externally induced longitudinal
currents
•
Auto ring trip
•
On-hook transmission (ANI) capability
•
Minimum protection circuitry required
•
Compatible with requirements of CDOT DOC/
FCC, CSA/UL,CCITT
•
Excellent power dissipation (SIL vertical
mounting)
MH88620IN
40 Pin SIL Package
0°C to 70°C
Description
Applications
•
•
April 1995
The Mitel MH88620IN SLIC provides all of the
functions required to interface 2-wire off premise
subscriber loops to a serial TDM, PCM, switching
network of a modern PBX. The MH88620IN is
manufactured using thick film hybrid technology
which offers high voltage capability, reliability and
high density resulting in significant printed circuit
board area savings. A complete line card can be
implemented with very few external components.
On/Off-Premise PBX Line Cards
Central Office Line Cards
VBat
LGND
RING
RF1
RF2
TIP
Matched
Feed
Resistors
VDD
LCA
Driver
Circuitry
and
Speech
Circuit
VEE
AGND
Switch-Hook
Threshold Set
Loop
Current
Set
Ring
Filter
Switch-Hook
Detect
TF1
SHK
TF2
2W/4W
Impedance
Network
Auto Ring
Trip
TRD
Test Relay
Driver
conversion
N2
Gain Adjust
Ring Relay
Driver
TRC RGND VRLY RNGC RRD
N1
Z1
Z2
GRX1 GRX0 RX GTX1 GTX0 TX
Figure 3 - Functional Block Diagram
2-159
MH88620IN
Preliminary Information
TIP
RING
TF1
TF2
RF1
RF2
LGND
LCA
VBAT
NC
RGND
VRLY
RRD
RNGC
NC
TRD
TRC
AGND
NC
N1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
N2
NC
Z1
Z2
TX
RX
GTX0
GTX1
GRX0
GRX1
NC
NC
NC
SHK
IC
IC
IC
IC
VEE
VDD
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Figure 2 - Pin Connections
Pin Description
Pin #
Name
1
TIP
2
RING
3
TF1
Tip Feed 1: Access point for balanced ringing. Normally connects to TF2.
4
TF2
Tip Feed 2: Access point for balanced ringing. Normally connects to TF1.
5
RF1
Ring Feed 1: Access point for balanced ringing. Normally connects to RF2.
6
RF2
Ring Feed 2: Access point for balanced ringing. Normally connects to RF1.
7
LGND
8
LCA
Current Limit Set (Input): The current limit is set by connecting an external resistor as
shown in Table 5. For 70mA default current, this pin is tied to -5V.
9
VBat
Battery Voltage: Typically -48V dc is applied to this pin.
10
RS1
Ring Sense Resistor Connection 1. See Figure 7a.
11
RGND
Ring Driver Ground Connection.
12
VRLY
Relay Supply Voltage Connection
13
RRD
Ring Relay Drive (Output). Connects to ring relay coil
14
RNGC
15
RS2
Ring Sense Resistor Connection 2. See Figure 7a
16
TRD
Test Relay Drive (Output): Connects to test relay coil.
17
TRC
Test Relay Control (Input).
18
AGND
19
NC
No Connection: Reserved.
20
N1
Network Balance Node 1. An external network balance impedance can be connected
between N1 and AGND. See Fig 4. for complex impedances. N2 no connection.
21
N2
Network Balance Node 2. See Fig 4. N2 connects to GND for 600Ω balance. N1 no
connection.
2-160
Description
Tip Lead. Connects to the TIP lead of the subscriber line
Ring Lead: Connects to the Ring lead of the subscriber line.
Battery Ground. VBAT return path. Connected to system’s energy dumping ground.
Ring Relay Control (Input)
Analog Ground: VDD and VEE. return path
MH88620IN
Preliminary Information
Pin Description (Continued)
Pin #
Name
Description
22
NC
No Connection. Reserved
23
Z1
Line impedance Node 1. Normally connects to Z2. See Fig. 3.
24
Z2
Line impedance Node 2. Normally connects to Z1. See Fig 3.
25
TX
Transmit (Output). 4-wire (AGND) referenced audio output.
26
RX
Receive (Input). 4-wire (AGND) referenced audio input.
27
GTX0
Transmit Gain Node 0. Connects to GTX1 for 0dB transmit gain.
28
GTX1
Transmit Gain Node 1. Connects to a resistor to AGND for transmit gain adjustment.
29
GRX0
Receive Gain Node 0. Connects to GRX1 for 0dB gain
30
GRX1
Receive Gain Node 1. Connect to a resistor to AGND for receive gain adjustment
31
NC
No Connection. Reserved
32
NC
No Connection. Reserved.
33
NC
No Connection. Reserved.
34
SHK
35.38
IC
39
VEE
Negative Supply Voltage. -5V dc.
40
VDD
Positive Supply voltage. +5V dc
Off-Hook Indication (Output). A logic low output indicates when the subscriber
equipment has gone Off-Hook.
Internal Connection.
2-161
MH88620IN
Preliminary Information
Absolute Maximum Ratings * All voltages are with respect to GNDA unless otherwise stated.
Parameter
1
Supply Voltages
2
Storage Temperature
Symbol
Min
Max
Units
65
6
6
V
V
V
+125
°C
LGND -VBat
VDD -GND
GND - VEE
-40
TS
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Recommended Operating Conditions† - Voltages are with respect to GNDA unless otherwise stated.
Characteristics
Sym
Min
1
Operating Temperature
TOP
0
2
Supply Voltages
VBat*
VDD
VEE
-44
4.75
-4.75
Typ*
-48
+5.0
-5.0
Max
Units
70
°C
-60
5.25
-5.25
V
V
V
Comments
* Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
† Voltages specified are with respect to LGND.
DC Electrical Characteristics*
Characteristics
1
Operating Loop Current
Sym
Min
Typ‡
ILoop
Max
Units
70
mA
mA
mA
17
16
Variation in Loop current
from nominal
2
3
mA
±2
SHK
RNGC
TRC
IBat
IDD
IEE
2
15
15
mA
mA
mA
RLoop = Open (On-hook)
On-Hook or Off-Hook
On-Hook or Off-Hook
Power Dissipation
PDo
PD1
2
250
W
mW
Active
Stand-by/Idle
Low Level Output Voltage
VOL
High Level Output Voltage
VOH
3.7
Low Level Input Voltage
High Level Input Voltage
VIL
VIH
2.4
Low Level Input Current
High Level Input Current
IIH
IIL
0.5
V
IOL = 400µA
V
IOH = 40µA
0.8
V
V
20
20
µA
µA
* DC 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.
2-162
RLoop = 0Ω, LCA = -5V
1500Ω
2000Ω VBat = -48V
Operating Current
4
5
ILoop
Test Comments
VIH = 5.0V
VIL = 0.0V
MH88620IN
Preliminary Information
AC Electrical Characteristics*
Characteristics
Sym
Min
1
Analog Tx Gain (T-R to TX)
2
Analog Rx Gain (RX to T-R)
3
Ringing Capability
25
4
On-hook Transmission
Signal input level
Gain
4
5
SHK Rise Time
Fall time
Typ‡
Max
0
0
tR
2.0
8
1
1
tF
Units
dB
Externally adjustable
dB
Externally adjustable
VRMS
RLoop = 1400Ω
Term. 6.8µF +200Ω
VRMS
dB
VBat = -48V
T-R load = 10Ωk min.
msec
msec
Dial Pulse Detection
6
2 Wire Termination Impedance
600
Ω
7
Off-Hook Detect Threshold
10
mA
8
2-Wire Return Loss
600Ω at T-R
9
Longitudinal Balance
Longitudinal to Metallic
10
Longitudinal Current Capability
11
Idle Channel Noise
Rx to T-R
T-R to Tx
N CR
NCX
Transhybrid Loss
THL
12
13
Adjustable
20
26
20
dB
dB
dB
300-500Hz
500-2500Hz
2500-3400Hz
58
55
53
dB
dB
dB
2000Hz, 1000Hz
2000Hz, 3000Hz
3400Hz
mA
20mA per lead
40
Tx gain 0dB
Rx gain 0dB
Test Comments
8
12
dBrnC
dBrnC
16
20
16
dB
dB
dB
Analog Signal Overload Level at
TIP and RING
4
dBm
14
Ringing Signal Voltage
70
80
90
VRMS
15
Ringing Frequency
20
25
30
Hz
16
Ring Trip Delay
17
Absolute Gain variation
18
Relative Gain, reference to 1kHz
19
Power Supply Rejection Ratio
VBAT
VDD
VEE
100
0
+.25
-2
0
+.2
24
24
24
T-R = 900Ω
VBAT = -48V
ms
-25
PSRR
300-500Hz
500-2500Hz
2500-3400Hz
dB
0dBm at T-R, 1kHz
dB
300-3400Hz
dB
1kHz, 100mVpp
30
30
30
* AC Electrical Characteristics are over Recommended Operating Conditions unless otherwise stated.
‡ Typical figures are at 25C with nominal ± 5V supplies and are for design aid only.
Note: Test Conditions use a transmit and receive gain set to 0dB default and a Zin value of 600Ω unless otherwise stated.
“Ref” indicates reference impedance which is equivalent to the termination impedance.
“Net” indicates network balance impedance.
2-163
MH88620IN
Preliminary Information
Transmit Gain (dB)
2-Wire to Tx 20log
(Tx/2-Wire)
RTX Resistor (1%)
Value (Ω)
+6.0
No Resistor
+4.0
38.3k
+3.7
32.4k
0.0
Connect GTX0 to GTX1
-3.0
5.49k
-6.0
3.32k
-12.0
1.43k
Notes
Results in 0dB overall gain when used with
Mitel A-law codec (i.e. MT8965)
Note 1: Overall gain refers to the receive path of PCM to 2-Wire.
Note 2: See Figure 2 for Application Circuit.
Receive Gain (dB)
Rx to 2-Wire 20log
(2-Wire/ Rx)
RRX Resistor (1%)
Value (Ω)
+6.0
No Resistor
Notes
0.0
Connect GRX0 to GRX1
-3.0
5.49k
-3.7
4.87k
-4.0
4.64k
-6.0
3.32k
-12.0
1.43k
Results in 0dB overall gain when used with
Mitel A-law codec (i.e. MT8965)
Note 1: Overall gain refers to the receive path of PCM to 2-Wire.
Note 2: See Figure 2 for Application Circuit.
75
ILoop
(mA)
Constant Voltage
Region
60
40
0
RLoop (ohms)
Graph 1 - I Loop/R Loop Characteristics
2-164
2k ohms
Preliminary Information
Functional Description
The SLIC uses a Transformerless electronic 2-4 wire
converter which can be connected to a Codec to
interface the 2 wire subscriber loops to a time
division multiplexed (TDM) pulse code modulated
(PCM) digital switching network. For analog
applications, the TXRX of the 2 wire converter can
be connected directly to an analog crosspoint switch,
such as the MT8816. Powering of the line is provided
through precision battery feed resistors. The
MH88620IN also contains control, signalling and
status circuitry which combines to provides a
complete functional solution, simplifying the
manufacture of line cards. This circuitry is illustrated
in the functional block diagram in Fig 1. The
MH88620IN is designed to be pin compatible with
Mitel’s MH88632, MH88625, MH88620, and
MH88628. This allows a common PCB design with
common gain, input impedance and network
balance.
MH88620IN
provides for long loop capability regardless of the
current setting. Refer to graph 1.
The LCA (Loop Current Adjust) pin is an input to an
internal resistor driver network which generates a
bias voltage. The loop current is proportional to this
voltage. The loop current can be set between 30 and
75 mA by various connections to the LCA pin as
illustrated in Table 5 and Figure 5. The loop current
during a fault condition will be limited to the constant
loop current programmed. Primary over current
protection is inherent in the current limiting feature of
the 200 ohm battery feed resistor. Refer to Graph 1.
Receive and Transmit Audio Path
The audio signal of the 2-wire is sensed differentially
across the 200 ohm feed resistor and is passed on to
a second differential amplifier stage in the 2W/4W
conversion block. This block sets the transmit gain
on the 4-wire side and cancels signals originating
from the receive input.
Approvals
Programmable Transmit and Receive Gain
FCC part 68, CCITT, DOS CS-03, UL 1459, CAN/
CSA-22.2 N0. 225-M90 and ANSI/EIA/TIA-464-A are
system level safety standards and performance
requirements. As a component of a system, the
MH88620IN is designed to comply with the
applicable requirements of these specifications.
Battery Feed
The loop current for the subscriber equipment is
sourced through a pair of matched 200 ohm resistors
connected to the TIP and RING. The two wire loop is
biased such that the Ring lead is 2V above VBAT
(typically -46V) and the Tip lead is 2V below LGND
(typically -2V) during constant voltage mode.
The SLIC is designed for a nominal battery voltage
of -48Vdc and can provide the maximum loop current
of 75mA under this condition.
The interface circuit is designed to be operated down
to a maximum of 16mA dc, with a battery voltage of 44V. The Tip and Ring output drivers can operate
within 2V of VBat and LGND rails.
Loop Current Setting
The MH88620IN SLIC is a constant resistance with
constant voltage fallback design. This design feature
Transmit Gain (Tip-Ring to Tx) and Receive Gain (Rx
to Tip-Ring) are programmed by connecting external
resistors (RRX and RTX) from GRX1 to AGND and
from GTX1 to AGND as indicated in Figure 2 and
Table 1 and 2. The programmable gain range is from
-12dB to +6dB; this wide range will accommodate
any loss plan. Alternatively, the default Receive Gain
of 0dB and Transmit Gain of 0dB can be obtained by
connecting GRX0 and GRX1 and GTX0 to GTX1. In
addition, a Receive Gain of +6dB and Transmit Gain
of +6dB can be obtained by not connecting resistors
RRX and RTX. For correct gain programming. the
MH88620IN’s Tip-Ring impedance (Z in) must match
the line termination impedance.
For optimum performance, resistors RRX should be
physically located as close as possible to the GRX1
input pin, and resistor RTX should be physically
located as close as possible to the GTX1 input pin.
Two Wire Port Termination Impedance
The AC termination of 600 ohms, of the 2W port is
set using active feedback paths to give the desired
relationship between the line voltage and the line
current. The loop current is sensed differentially
across the two feed resistors and converted to a
single ended signal. This signal is fed back to the
2-165
MH88620IN
Tip/Ring driver circuitry such that impedance in the
feedback path gets reflected to the two wire port.
The MH88620IN’s Tip-ring impedance (Zin) is
designed to be 600Ω, when used with 25Ω PTC’s as
protection circuitry. For this requirement, Z1 and Z2
should be connected together on the PCB. To
accommodate the use of lower value PTC’s a series
resistance can be connected between Z1 and Z2.
For example, if two 8Ω PTCs are used, connect
340Ω between Z1 and Z2.
The design uses a 0.1 times impedance amplifier so
the 340Ω actually adds 34Ω of additional impedance
to the 550Ω (16 + 34 +550 = 600). For complex
impedance setting, a capacitor and/or resistor can
be connected between Z1 and Z2. For example, if
Return Loss is to be maximized for a Zin of 600
+2.2µF, a 0.22µF cap can be connected between Z1
and Z2.
Network Balance
Transhybrid loss is maximised when the line
termination impedance and SLIC network balance
are matched. The MH88620IN’s network balance
impedance can be set to Zin, or to a user selectable
value. Thus, the network balance impedance can be
set to any Indian or other international requirement.
An external Network Balance impedance is selected
which 0.1 times the impedance between N1 and
AGND. N2 to GND balances to 600 ohms.
Off-Hook and Dial Pulse Detection
The SHK pin goes low when the DC-loop current
exceeds a specified level. The threshold level is
internally set by the bias voltage of the switch-hook
detect circuitry. Dial pulses can be detected by
monitoring the interruption rate at the SHK pin.
These dial pulses would be debounced by the
system software.
Ring Trip Detection
The interface permits detection of an Off-Hook
condition during ringing. If the subscriber set goes
Off-Hook when the ringing signal has been applied,
the DC loop current flow will be detected within
approximately 100msecs and the SHK output will go
low. The Ring relay is automatically disabled by the
internal hardware.
2-166
Preliminary Information
Longitudinal Balance
The longitudinal balance specifies the degree of
common mode rejection in the 2 to 4 wire direction.
Precision laser trimming of internal resistors in the
hybrid ensures good overall longitudinal balance.
The interface circuitry can operate in the presence of
induced longitudinal currents of up to 40 mA RMS at
60 Hz.
DTMF
The DTMF tones are transmitted and received at the
4-wire port.
High voltage Capability
Inherent in the thick-film process is the ability of the
substrate to handle high voltage. The standard Mitel
thick-film process provides dielectric strengths of
greater than 1000 VAC or 1500 VDC. The thick-film
process allows easy integration of surface mount
components such as the high voltage bipolar power
transistor line drivers. This allows for simpler, less
elaborate and less expensive protection circuitry
required to handle high voltage transients and fault
conditions caused by lightning, induced voltages and
power line crossings.
On-Hook Transmission
The MH88620IN provides for on-hook transmission
which supports features such as Automatic Number
Identification (ANI). The ANI information is a FSK or
DTMF signal originating from and sent by the C.O.
during the off period of the ringing voltage being sent
to the subscriber’s set. The subscriber’s set decodes
the identification signal and displays the calling
party’s number.
Applications
As shown in the application diagram, Figure 7a, the
ringing voltage, typically 80 V RMS 25Hz biased at -48
VDC, is applied to the subscriber line through an
external relay, K1, Enabling of the relay is performed
by applying a logic high level to the relay driver
control input, RRC.
Figure 7b, shows how balanced ringing can be
accommodated if required.
MH88620IN
Preliminary Information
or system ground. This is a seperate conductor from
LPGND or AGND on the line care PCB. D2 and D4
conduct the energy into a -VBat supply which is a
seperate conductor from the -VBat feed supply to the
SLICs. A power MOSFET circuit as shown in Figure
8, can be used to divert the energy normally dumped
into -V Bat, the EDG conductor. Usually one MOSFET
circuit can be used for 16 SLICs or per line card.
Protection Circuitry
Primary protection, from lightning strikes and AC line
faults, is normally located in the MDF (main
distribution feeder) which is located external to the
PABX or CO switching system. The primary
protection circuitry is normally housed in a 5-pin
connector and consists of either carbon blocks, with
spark gaps (older technology), gas discharge tubes
or high current semiconductor suppressors and
series heat coils. The 5-pin module usually limits the
high voltage to approximately 300 to 500 volts before
entering the switching system.
Depending on the additional level of protection
required, PRO1 and/or PRO2 protectors may be
used. These are used to protect the SLICs Ring
sense resistor and/or Ring generator from being
damaged if a fault condition occurs during the
application of Ringing to the line. PRO2 can be
implemented using two back to back zener diodes, or
an equivalent transient suppressor. The clamping
voltage should be >16 Vdc and <26Vdc. PRO2 may
not be required depending on the value and power
dissipation of PRO1.
Secondary protection, in the switching system, is
required to further limit these high voltages/currents.
Secondary protection is normally implemented on
each line card and is designed to protect the SLICs
from permanent damage. The basic secondary high
voltage protection circuitry for the MH88620IN, as
illustrated in Figure 7, consists of PTC1, PTC2 and
clamping diodes D1 to D4. During a fault condition,
the diodes clamp the overvolt Ground and -VBat.
PTC1 and PTC2 current limit as their resistance
increases with power dissipation caused by the overa voltage/over-current condition. The ground that D1
and D3 are connected to, must be an EDG (energy
dumping ground) which is connected to the chassis
Loop Length
The MH88620IN can accommodate loop lengths of
up to 2000 ohms minimum (including the subscriber
equipment). This corresponds to approximately 8km
using #26 AWG twisted pair or 15km using #24 AWG
twisted pair.
MH88620IN
MH88620IN
24
24
A.
23
Z1
24
Z2
Z2
R
Internal
5500 Ω
MH88620IN
Z2
23
R
Internal
5500 Ω
Z1
External
0.22µF
R
Internal
5500 Ω
B.
Ζ1
R
External
340Ω
C.
Notes
a) to accommodate the use of 2 x 25Ω PTCs, connect Z1 and Z2 together, Zin = 600Ω.
b) to accommodate the use of 2 x 8Ω PTCs, connect 340Ω between Z1 and Z2 = 600Ω.
c) to accommodate the use of 2 x 25Ω PTCs, connect 0.22µF between Z1 and Z2 = 6.0Ω + 2.2µF.
Figure 3 - Input Impedance (Zin) setting
2-167
MH88620IN
Preliminary Information
MH88620IN
N1
RP
10 x
NETBAL
R Internal
9000 Ω
N1
N2
CP
RS
1
ZNETBAL = 0.1 x RS +
1/RP + (SxCP)
[
where S = j x w
and w = 2 x π x f
Notes:
Example:
1) The 10xZin network must be set to 10 x the desired input Zin (impedance).
2) The 10 x NETBAL network must be set to10x the desired network balance.
3) Make connection between N1 and component as short as possible.
If RS =0Ω, RP = 800Ω, CP=.5nF
Then the network balance is 800Ω in
parallel with 50nF.
Figure 4 - External Network Balance Setting
Loop Current
LCA Pin Connection
Reference Fig#
20
Connect 10kΩ from LCA to +5V.
5a
25
Connect 16kΩ from LCA to +5V.
5a
30
Connect 36kΩ from LCA to +5V.
5a
35
Leave LCA open circuit.
5c
40
Connect 24kΩ from LCA to -5V.
5b
45
Connect 10kΩ from LCA to -5V.
5b
50
Connect 5.6kΩ from LCA to -5V.
5b
55
Connect 2.4kΩ from LCA to -5V.
5b
60
Connect 1.3kΩ from LCA to -5V.
5b
65
Connect 680kΩ from LCA to -5V.
5b
70
Connect from LCA to -5V.
5d
Table 5 - Loop Current Setting
+5V
R
LCA
LCA
LCA
LCA
-5V
-5V
5a
5b
5c
Figure 5 - Loop Current Setting
2-168
5d
]
MH88620IN
Preliminary Information
MH88620IN
Z
Transmit Gain:
Z
TX
(Tip-Ring to Tx)
25
AV= -20log
10kΩ
GTX1 28
10kΩ
]
[ 0.5+3kΩ
RTX
RTX
GTX0 27
Example
RTX=38kΩ; AV= +4dBV
Z
Z
RX
10kΩ
26
GRX1 30
GRX0
10kΩ
RRX
Receive Gain:
(RX to Tip-Ring)
AV= -20log
[ 0.5 + 5kΩ ]
RRX
29
Example:
RRX= 4.6kΩ; AV= -4dBV
Figure 6 - Gain Programming with External Components
2-169
MH88620IN
Preliminary Information
-VBat
FDi C2i
CSTi
-5 +5
+5V
SYSTEM
GROUND
VDD
RX
VBat
GRX0
VEE
TERM
AGND
MH88620IN
-5V
GRX1
LCA
TX
VR
VX
SDo
CODEC
FLi
Timeslot
Assignment
Circuit
GTX0
GTX1
SHK
UD
C2i
F1i
Status
Mux
Circuit
Z1
P
R
O
T
E
C
T
I
O
N
TIP
VRLY
RF1
K1
Z600
RNGC
RING
RRD
K1
REVC
RF2
RS1
RS2
NS
90VRMS 20Hz
-VBat
Figure 7a - OPS SLIC Configuration Applications Circuit
2-170
DSTi
CA
TF1
TF2
DSTo
MT896X
CA
CSTo
MH88620IN
Preliminary Information
-VBat
CSTi
FDi C2i
-5 +5
+5V
SYSTEM
GROUND
VDD
-5V
TERM
AGND
MH88620IN
VEE
RX
VR
GRX0
VX
GRX1
SDo
V Bat
LCA
TX
DSTo
CODEC
SUBSCRIBER 1
FLi
DSTi
CA
Timeslot
Assignment
Circuit
GTX0
TF1
TF2
GTX1
SHK
C2i
F1i
CA
Status
Mux
Circuit
CSTo
Z1
RNGC
VRLY
RING
RF1
45Vrms
20Hz
Z2
TIP
P
R
O
T
E
C
T
I
O
N
+
~
RRD
K1
REVC
RF2
~
+
45Vrms
20Hz
-VBat
NS
Figure 7b - OPS SLIC Configuration Applications Circuit - Balanced Ringing
2-171
MH88620IN
Preliminary Information
GND
MH88620IN
D1
T
PTC1
D2
V Bat
PRO1
GND
D3
R
PTC2
D4
VBat
Suggested Components
PRO1
Solid State Transient Suppressor, e.g., TISP2300L, P2703AB, MOV’s
or diode clamps D1-D4 to VBat and LPGND
PTC1, PTC2 Typical 25 Ω
Figure 8 - Suggested Protection Circuit
0.080 Max
(2.0 Max)
4.20 + 0.020
(50.8 + 0.5)
Side View
0.58+0.02
(14.7+0.5)
1 2 3 4
39 40
0.010 + 0.002
(0.25 + 0.05)
0.12 Max
(3.1 Max)
*
0.05 + 0.01
(1.3 + 0.5)
Notes:
1) Not to scale
2) Dimensions in inches).
3) (Dimensions in millimetres).
*Dimensions to centre of pin &
tolerance non accumulative.
*
0.05 + 0.02
(1.3 + 0.05)
*
0.020 + 0.05
(0.51 + 0.13)
Figure 9 - Mechanical Data
2-172
*
0.100 + 0.10
(2.54 + 0.13)
0.18 + 0.02
(4.6 + 0.5)