2
Agere Systems Inc.
Data Sheet
November 2001
L9218A/G Low-Cost Line Interface
Table of Contents
Contents
Page
Figures
Page
Features ......................................................................1
Description...................................................................1
Pin Information ............................................................4
Functional Description.................................................6
Absolute Maximum Ratings (at T
A
= 25
°
C) ................7
Recommended Operating Conditions .........................7
Electrical Characteristics.............................................8
Ring Trip Requirements..........................................12
Test Configurations ...................................................13
Applications...............................................................15
dc Applications....................................................... 19
Battery Feed.........................................................19
Current Limit.........................................................19
Overhead Voltage ............................................... 19
Loop Range..........................................................20
Off-Hook Detection...............................................20
Ring Trip Detection...............................................21
Longitudinal Balance.............................................. 21
ac Design............................................................... 22
Codec Types........................................................22
ac Interface Network ............................................22
Receive Interface .................................................22
Example 1: Real Termination (First-
Generation Codec).............................................. 23
Example 2: Complex Termination (First-
Generation Codec)...............................................25
Power Derating...................................................... 27
Pin-for-Pin Compatibility with L9217/L9219........... 27
PCB Layout Information ............................................27
Outline Diagram.........................................................28
28-Pin PLCC.......................................................... 28
Ordering Information..................................................29
Figures
Page
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10. ac Gains..................................................14
Figure 11. Basic Loop Start Application
Circuit Using T7504-Type Codec............15
Figure 12. Basic Loop Start Application
Circuit Using T8536-Type Codec............17
Figure 13. Loop Current vs. Loop Voltage...............19
Figure 14. Off-Hook Detection Circuit......................20
Functional Diagram...................................3
28-Pin PLCC.............................................4
Ring Trip Circuits....................................12
L9218 Basic Test Circuit.........................13
Metallic PSRR.........................................13
Longitudinal PSRR .................................13
Longitudinal Balance ..............................14
RFI Rejection..........................................14
Longitudinal Impedance..........................14
Figure 15. Ring Trip Equivalent Circuit and
Equivalent Application ........................... 21
Figure 16. ac Equivalent Circuit.............................. 23
Figure 17. Interface Circuit Using First-
Generation Codec (
±
5 V Battery) .......... 26
Figure 18. Interface Circuit Using First-
Generation Codec (5 V Only Codec)..... 26
Tables
Page
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 9.
Pin Descriptions ...................................... 4
Input State Coding .................................. 6
Supervision Coding ................................. 6
Power Supply .......................................... 8
2-Wire Port .............................................. 9
Analog Pin Characteristics .................... 10
ac Feed Characteristics
......................11
Parts List for Loop Start Application
Circuit Using T7504-Type Codec .......... 16
200
+
680
||
0.1
μ
F First-
Generation Codec Design Parameters . 17
Parts List for Loop Start Application
Circuit Using T8536-Type Codec .......... 18
Table 10.
Table 11.