Data Sheet
May 2001
L8576B Dual Ringing SLIC
Contents
Table of Contents
Page Figures
Page
Features ......................................................................1
Applications .................................................................1
Description...................................................................1
Pin Information ............................................................5
Functional Description.................................................7
General .....................................................................7
Protection..................................................................7
Tip/Ring Drivers ........................................................7
Battery Operation......................................................7
Transmit and Receive Interface................................7
Data Interface ...........................................................8
Loop Current Detector ..............................................8
Operating States..........................................................8
Absolute Maximum Ratings ........................................9
Electrical Characteristics ...........................................10
Test Configurations .................................................. 14
Applications ..............................................................15
Characteristic Curves..............................................15
dc Design................................................................17
Power Ringing.........................................................18
ac Design................................................................19
Use of an Auxiliary Battery Supply..........................24
Outline Diagram ........................................................25
44-Pin PLCC...........................................................25
Ordering Information .................................................26
Figure 1. Architectural Diagram ................................. 3
Figure 2. Typical 600 Ω Application Circuit (Only
One Channel Shown) ................................. 4
Figure 3. 44-Pin PLCC Pin Diagram .......................... 5
Figure 4. Pretrip Circuit ............................................ 11
Figure 5. Basic Test Circuit ..................................... 14
Figure 6. Metallic PSRR .......................................... 14
Figure 7. Longitudinal PSRR ................................... 14
Figure 8. Longitudinal Balance ................................ 15
Figure 9. Longitudinal Impedance ........................... 15
Figure 10. ac Gains ................................................. 15
Figure 11. Receive Gain and Hybrid Balance vs.
Frequency .............................................. 15
Figure 12. Transmit Gain and Return Loss vs.
Frequency .............................................. 15
Figure 13. Loop Current vs. Loop Voltage ............... 16
Figure 14. Loop Current vs. Loop Resistance ......... 16
Figure 15. SLIC Power Dissipation vs. Loop
Resistance (VBAT = –48 V) ...................... 16
Figure 16. SLIC Power Dissipation vs. Loop
Resistance (VBAT = –65 V) ...................... 16
Figure 17. Loop Current vs. Loop Voltage ............... 17
Figure 18. Ringing Waveform Crest Factor = 1.6 .... 18
Figure 19. Ringing Waveform Crest Factor = 1.2 .... 18
Figure 20. ac Equivalent Circuit Using a T8503
Codec ..................................................... 20
Figure 21. ac Interface Circuit Using First-
Tables
Page
Generation Codec (Blocking Capacitors
Not Shown) ............................................. 22
Table 1. Pin Descriptions ............................................5
Table 2. Input State Coding ........................................9
Table 3. Operating Conditions and Powering ...........10
Table 4. Ring Trip Detector ......................................10
Table 5. Battery Feed ...............................................11
Table 6. Analog Signal Pins .....................................12
Table 7. ac Feed Characteristics ..............................12
Table 8. Isolation Between Channels .......................13
Table 9. Data Interface and Logic ............................13
Figure 22. ac Interface Circuit Using First-
Generation Codec (Including Blocking
Capacitors) ............................................. 23
2
Agere Systems Inc.
AGERE [ AGERE SYSTEMS ]
