PBL 387 10/1
The PBL 387 10/1 ring SLIC (Subscriber Line Interface Circuit) is a bipolar integrated
circuit in 90 V technology which replaces the conventional transformer based analog
line interface and ringrelay in FITL, WLL, ISDN-TA and other telecommunications
equipment with a modern, compact solid state design. Not only is required PCB area
reduced, but less component weight and height result as well. The PBL 387 10/1 has
been optimized for low cost and to require only a minimum of external components.
The PBL 387 10/1 constant-current feed system, programmable to max 40 mA of
line current, can operate with battery supply voltages down to -21 V to reduce line
card power dissipation.
The SLIC incorporates loop current, ground key and ring trip detection functions.
Two-to four-wire and four- to two-wire voice frequency (vf) signal conversion is
accomplished by the SLIC in conjunction with either a conventional CODEC/filter or
with a programmable CODEC/filter (e.g. SLAC, SiCoFi, Combo II). The programmable
line terminating impedance could be complex or real to fit every market.
The PBL 387 10/1 package is 28-pin PLCC.
· Ring SLIC eliminates ring relay and
· Supports sine wave and trapezoidal
· -85 V battery feed for high voltage ring
· On chip automatic battery switch
· Programmable battery feed
· Battery supply voltage as low as -21 V
for power efficient line card designs
· Low on-hook power dissipation,
50 mW @-24 V battery
· Loop current, ring trip and ground key
· Programmable loop current detector
· Programmable ring trip detector
· Hybrid function with all types of
· Programmable line terminating
impedance, complex or real
· On-hook transmission
· Tip-ring open circuit state for
subscriber loop power denial
Figure 1. Block diagram.