MITEL MH88628 Datasheet



MH88628

Central Office SLIC

Preliminary Information

Features

• Programm able gain, ne twork bal anc e and
impedance

• Transformerless 2-4 wire conversion

• Constant cu rren t with co nstan t volta ge fall back
for long loop capability

• Pin compa tible wit h MH8 8632, M H8 8620 an d
MH8862 8

• Unbalanc ed detec tion (Tip, Ring grou nd
sensing)

• Auto ring trip wi th zer o cross ing

• On-Hook tran smissi on (A NI) cap ability

• Compatible with require men ts of CCI TT,
DOC/FCC and CSA /UL

• Excellent power dissipation (SIL vertical
mountin g)

• 12/16kHz meter pulse injection control

• Solid State TIP/RING reversals

• Ringing amplifier

ISSUE 5 April 1995

Ordering Information

MH88628 40 Pin SIL Pac kage

0°C to 70°C

Applications

• On/Off Premise PBX Line Cards

• DID (Direct Inward Dial) Line Cards

• Central Office Line Ca rds

Descript io n

The Mitel MH88628 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 MH88628 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 C.O. line card can
be implemented with very few external components.

RING

RF1
RF2

TIP
TF1
TF2

UD

VRLY

RNGD

RD

VBat LGND

Matched

Feed

Resistors

Unbalanced

Detection

Decoder

Circuit

SEL1 SEL2 ACRI DCRI ESI ESE Z600 Z1Z900 Z2 GRX1 GRX0 RX GTX1 GTX0 TX

Ringing

Amplifier

Driver

Circuitry

and

Speech

Circuit

External

Signal

Input

LCA VDD

Loop

Current

Set

Impedance

Network

VEE

Switch-hook

Threshold Set

Switch-hook

Detect

AGND

Ring

Filter

2-4 Wire

Conversion

Gain Adjust

Figure 1 - Functio nal Blo ck Diag ram

SHK

NS
N1

N2
NATT

2-199

MH88628 Preliminary Information

TIP

RING

TF1

TF2
RF1
RF2

LGND

LCA

VBat
DCRI

RGND

VRLY

RD
SEL1
SEL2

ESI

ESE

AGND

NATT

N1

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

N2

Z900

Z1
Z2
TX

RX
GTX0
GTX1

GRX0
GRX1

ACRI

Z600

NS

SHK

UD

IC
IC

IC
VEE
VDD

Figure 2 - Pin Connections

Pin Description

Pin # Name

1TIPTip Lead. Connects to the “Tip” lead of subscriber line.
2 RING Ring Lead. Connects to the “Ring” lead of the subscriber line.

Description

21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

3TF1Tip Feed 1. Access point for balanced ringing. Normall y connects to TF2.
4TF2Tip Feed 2. Access point for balanced ringing. Normall y connects to TF1.
5RF1Ring Feed 1. Access p oint for balanced ringi ng. Norm all y connect s to RF2.
6RF2Ring Feed 2. Access p oint for balanced ringi ng. Norm all y connect s to RF1.
7 LGND Battery Ground. VBat return path. Connected to system’s energy dumping ground.
8LCACurrent Limit Set (Input). The current limit is set by connecting an external resistor to

ground. For 30mA defa ult current, this pin is tied to GND.

9VBatBattery Voltage. Typically -48Vdc is applied to this pin.
10 DCRI DC Ringing Voltage Input. A continu ous 120V dc is applied to this input.
11 RGND R e lay Dri ver Gr oun d Connec tio n.
12 VRLY Relay Supply Voltage Connection.
13 RD

Ring Drive (Output). Connects to ring rel ay coil.
14 SEL1 Sel ect 1 (Inp ut). Refer to Table 5
15 SEL2 Sel ect 2 (Inp ut). Refer to Table 5.
16 ESI External Signal Input. 12/16kHz meter pulse input.
17 ESE External Signal Enable. Applies the external signal to the line.
18 AGND Analog Gr ound. VDD and VEE return path.
19 NATT Network Balance AT+T Node. Connects to N1 for a network balance impedance of AT&T

compromise (350Ω + 1k Ω // 210nF); the device’s input impedance must be set to 600Ω.

This node is active only when NS is at logic high. This node should be left open circuit when

not used.

2-200

Preliminary Information MH88628

Pin Description (Continued)

Pin # Name

Description

20 N1 Network Balance Node 1(Input). 0.1 times the impedance between pins N1 and N2 must

match the device’s input impedance, while 0.1 times the impedance between pins N1 and
AGND is the device’s network balance impedance. This node is active only when NS is at

logic high. This node may be terminate d when not used (i.e., NS at logic low).
21 N2 Network Balance Node 2 (Output). See N1 for description.
22 Z900 Line Impedan ce 900Ω Node. Connects to Z1 for a line impedance of 900Ω. This node

should be left open circuit when not used.
23 Z 1 Line Impedance Node 1 (Input). 0.1 times the times the impedance between pins Z1 and

Z2 is the device’s line impedance. This node must always be connected.
24 Z 2 Lin e Impedan ce Nod e 2 (Outpu t). 0.1 times the tim es the impeda nce betwee n pins Z1

and Z2 is the device’s line impedance. This node should be left open circuit when not used.
25 TX Transmit (Output). 4-Wire (AGND) referenced audio output.
26 RX Receive (Input). 4-Wire (AGND) referenced audio input.
27 G TX0 Transmit Gain Node 0. Connects to GTX1 for 0dB transmit gain.
28 G TX1 Transmit Gain Node 1. A resistor to AGND provides transmit gain adjustment.
29 GRX0 Receive Gain Node 0. Connects to GRX1 for 0dB gain.
30 GRX1 Receive Gain Node 1. A resistor to AGND provides receive gain adjustment.
31 AC RI AC Ringing Voltage Input. A 1.5Vrms 20Hz signal is applied to this input.
32 Z600 Line Impedan ce 600

Ω Node (Output). Connects to Z1 for a line impedance of 600Ω.

This pin should be left open circuit when not used.
33 NS Network Balance Setting (Input). The logic level at NS selects the net work balance

impedance. A logic 0 enables an internal balance equivalen t to the input impedance (Z

While a logic 1 enables an external balance 0.1 times the impedance between pins N1 and

AGND balanced to 0.1 times the impedance betwe en pins N1 and N2. The impedan ce

).

in

34 SHK

between N1 and N2 must be equivalent to 10 times the input impedance (Z

Off-Hook Indication (Output). A logic low output indicates when the subscriber equipment

has gone Off-Hook.
35 UD

Unbalance Detect (Output). A log IC low output indicates when the DC current flow in the

Tip and Ring leads is unbalanced, indicating that the subscriber equipment has grounded

the Ring lead.

36,37,38

IC Internal Connection. These pins are internally connected and must be left open
39 VEE Negative Su pp ly Voltage. -5V dc.
40 VDD Positive Supply Voltage. +5V dc.

).

in

2-201

MH88628 Preliminary Information

Absolute Maximum Ratings*

Parameter Sym Min Max Units Comments

1 Supply Voltage V

2 Storage Temperature T

* Exceeding these values may cause pe rman ent dama ge. Functi on al operati on under these co ndition s is not implie d.

V

Bat

V

DD

V

DCRI

EE

S

+0.3

-0.3

+0.3

-0.3

65

6

-6

140

-40 +125 °C

V

With respect LG ND
V
V
V

Recommended Operating Conditions

Parameter Sym Min Typ* Max Units Comments

1 Supply Voltage V

2 Operating Temperature T

Bat

V

DD

V

EE

OP

-44

4.75

-4.75

-48

+5.0

-5.0

-60

5.25

-5.25

V
V
V

02070°C

3 AC Ring Generator

Voltage

Frequency 17

90

33

Vrms

Hz

4 DCRI

Input DC Voltage V

* Typical figures are at 25° C with nominal + 5V supplies for design aid only.

DCRI

110 120 130 Vdc

DC Electrical Characteristics‡

Characteristi cs Sym Min Typ* Max Uni t s Test Conditio ns

1 Operating Loop Current

Var in loop current from nominal

2 Operating Currents I

I

Loop

I

Loop

I

Loop

I

Loop

I

I

Bat

Bat

DD

I

3 Power Di ssipation PD

PD

16

EE

O

1

45
30

± 2

32

2

25
25

2

300

4

SHK

UD

5 SEL1

SEL2

ESE

6 High Level Input Current

NS

‡ DC Electrical Characteristics are over recommended operating conditions unless otherwise stated.
* Typical figures are at 25°C with nominal

Low level Output Voltage
High Level Output Vo ltage

Low Level Input Voltage
High Level Input Voltage

Low Level Input Current

+5V supplies and are for design aid only.

V

OL

V

OH

V

IL

V

IH

I

IH

I

IL

3.7

2.4

0.5 V

0.8 V

20
20

mA
mA
mA
mA

mA
mA
mA

mA

W

mW

V

V

µA
µA

=0Ω

R

Loop

2300Ω VBat =-48V

=0Ω, LCA -

R

Loop

GND

R

=0 (off Hook),

Loop

LCA=GND

= open (On-

R

Loop

Hook)
On-hook or Off-Hook
On-Hook or Off-Hook

Active
Standby/Idle

I

= 400µ A

OL

= 40µA

I

OH

VIH=5.0V

=0.0V

V

IL

2-202

Preliminary Information MH88628

AC Electrical Characteristics‡

Characteristics Sym Min Typ* Max Units Test Conditions

1 TX Gain 0 dB externa l ly adj ustab le
2 RX Gain 0 dB externally adjustable
3 Ringing Capability 5 REN
4 On-Hook Transmission

V

Signal Input Level
Gain 6

5 External S ignal Outp ut Level 1.75 2.25 V

6SHK

Rise Time

Fall time

7 2-Wire Term inat ion

Impedance

t

R

t

F

1
1

600/

900

2.0 V

rms

dB

rms

ms
ms

Ω

8 Off-Hook Det ect Threshold 10 mA
9 2-Wire Return Lo ss 20

20
20

dB
dB
dB

10 Longitudi nal Balance

Longitundinal to Metallic 58

11 Longitudinal Current

53

40 mA 20mA per lead

dB
dB

Capability

12 Idle channel Noise

Rx to T- R

T-R to Tx

N

CR

N

CX

8

12

dBrnC

dBrnC
13 Transhybrid Loss THL 22 40 dB 200-3400Hz
14 Unbalanced Detect Threshold I

UB

10 mA

15 Analog Signal Overload Level

At Tip and Ring 4 dBm

16 Ringing Signal Voltage 90 Vrms

=-48V

Bat

T-R load = 10kΩ min.
V

= -48V, T-R load=

Bat

200Ω LCA=0V, Zo-600Ω,
Gain=0 dB

Dial Pulse De te c ti on

Selectable

300 to 500Hz
500 to 2500Hz
2500 to 3400Hz

200-1000Hz
1kHz - 3k4Hz

T- R=600Ω, V

Bat

=-48V

17 Ringing Frequency 17 33 Hz
18 Ring Trip Delay 100 ms
19 Absolute Gain, Variation +
20 Relative Gai n, refere nce to

0.1 dB 0dB at T-R, 1kHz

+

0.05 dB 300-3400Hz

1kHz

21 Power Supply Rejection Ratio

V
V

V

* Typical figure are at 25°C with nominal +5V supp lies and are for desig n aid only.
‡ AC Electrical Characteristics are over recommended operating conditions unless otherwise stated.

Notes:
Impedance set by external networ k of 600Ω or 900Ω default.
External network for test purposes consists of 2200Ω + 8200 Ω // 11. 5nF between pins Z1 and Z2, the equivalent Zin has 1/10
and is equivalent o 220Ω+820Ω // 115nF.
Test condition uses a Zin value of 600Ω, 900Ω and the above external network.
Test condition s 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 ne two rk bala nce impe dance.
Refer to Table 1, 2 for TX, RX gain adjustme nt.

Bat
DD

EE

PSRR

dB 1kHz, 100mVpp
24
24
24

th

the im pe dance

2-203