MH88612K

® 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 tipring 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 MH88612K TF RF IC IC IC IC IC TIP IC RING RC2 LPGND IC VR VRef CAP SHK GNDA VEE VDD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 TF VBat RV PD VX IC IC VRLY RC1 RD1 Preliminary Information 21 22 23 24 25 26 27 28 29 30 Figure 2 - Pin C...