®
MH88612K
Subscriber Line Interface Circuit
Preliminary Information
Features
•
•
•
•
•
•
•
•
•
•
Input impedance 600
Ω
Transformerless 2-wire to 4-wire conversion
Battery and ringing feed to line
Off-hook and dial pulse detection
Ring ground over-current protection
Adjustable constant current feed
Relay drive output with diode protection
Power Denial
Wide V
BAT
Operating Range
Tip/Ring Reversal
MH88612K
ISSUE 3
April 1995
Ordering Information
30 Pin SIL Package
0°C to 70°C
Description
The SLIC provides a complete interface between a
switching system and subscriber loop. Functions
provided include battery feed, ringing feed and tip-
ring reversal to the subscriber line, 2-Wire to 4-Wire
hybrid interfacing, constant current feed and dial
pulse detection. The device is fabricated as a thick
film hybrid using various technologies.
Applications
Line interface for:
• PABX
•
•
•
Intercoms
Key Telephone Systems
Control Systems
LPGND
RF
TF
TIP
RING
T/R
Reverse
VBat
PD
VDD VEE GNDA
Power
Denial
Battery
Feed
2-Wire to
4-Wire
Conversion
VR
VX
RC2
T/R Reverse
Relay Driver
Over Current
Protection
VRLY
RD1
RC1
Relay
Drive
Circuit
Constant
Current
Feed
Loop
Supervision
VRef
CAP
RV
SHK
Figure 1 - Functional Block Diagram
2-121
MITEL [ MITEL NETWORKS CORPORATION ]
