Description
The Mitel MT91610, with an external bipolar driver (Figure 4), provides an interface between a switching system and a subscriber loop. The functions provided by the MT91610 include battery feed, programmable constant current with constant voltage fold over for long loop, 2W to 4W conversion, offhook and dial pulse detection, direct balance ringing with built in ring tripping, unbalance detection, user definable line and network balance impedance’s and gain, and power down and wake up. The device is fabricated as a CMOS circuit in a 36 pin QSOP package.

Features
• Transformerless 2W to 4W conversion
• Controls battery feed to line
• Programmable line impedance
• Programmable network balance impedance
• Off-hook and dial pulse detection
• Protects against GND short circuit
• Programmable gain
• Programmable constant current mode with constant voltage fold over
• Transformerless balanced ringing with automatic ring trip circuit. No mechanical relay
• Supports low voltage ringing
• Line polarity reversal
• On-hook transmission
• Power down and wake up capability
• Meter pulse injection
• Ground Key detection

Applications
Line interface for:
• PABX
• Intercoms
• Key Telephone Systems
• Control Systems