PBL38772-1

www.DataSheet4U.com Advance Information PBL 387 72/1 Subscriber Line Interface Circuit Key Features VCC On-chip high voltage ring generation - Balanced, up to 80 VPeak - Any ring waveform - 5 REN ringing load - Short circuit safe - Automatic gain control of ringing signal Low on-hook power consumption in Active State (65mW @ VBat=-80V) Automatic switching between ringing battery (VBat) and talk battery (VTBat) Only +5V and Battery supplies needed Pulse metering and on-hook transmission UL-1950 and MTU compliant on-hook line voltage Programmable ring trip threshold 3.3V compatible logic interface Silent or fast polarity reversal 28-pin SOIC package VT BA T AGND PRT C1 R in g T rip D e te cto r VBAT BGND C2 In p u t TIPX HP C3 Decoder and C o n tro l DE T R IN G X Li ne Feed Co n trol ler Tw o -w ire In terfa ce PL C LP REF SPR and Longi tu d inal S ignal S uppr es sion O ff-h o o k D e te cto r PL D VT X V F S ignal T rans m ission VTB R ingi ng C ont rol C R IN G VR RS N Figure 1. Block diagram up to 80 VPeak (85 V dc supply) to the subscriber line across a load of up to 5REN The PBL 387 72/1 supplies programmable constant current to the subscriber loop, sourced from the talk battery. The onhook line voltage of 43 V to 56 V is derived from the ring battery. All battery switching is internal to the device and is automatic. To further reduce power consumption the automatic gain control for the ring signal (AGCR) keeps the level always adjust...