T7256 Agere Systems, T7256 Datasheet - Page 7

• Manufacturer Part Number: T7256
• Description: (T7234 - T7256) Compliance
• Manufacturer: Agere Systems

Lucent Technologies Inc.
February 1998
Figures
Figure 1. Block Diagram ......................................................................................................................................... 4
Figure 2. Pin Diagram............................................................................................................................................. 4
Figure 3. U-Interface Frame and Superframe ........................................................................................................ 8
Figure 4. U-Interface Superframe Bit Groups......................................................................................................... 9
Figure 5. Frame Structures of NT and TE Frames ............................................................................................... 10
Figure 6. Details of NT and TE Frames................................................................................................................ 11
Figure 7. U-Interface Quat Example..................................................................................................................... 12
Figure 8. S/T-Interface ASI Example.................................................................................................................... 13
Figure 9. Location of the Loopback Configurations (Reference ITU-T I.430 Appendix I)..................................... 14
Figure 10. STLED Control Flow Diagram ............................................................................................................. 16
Figure 11. T7234 Stand-Alone Reference Circuit-A ............................................................................................. 19
Figure 12. T7234 Stand-Alone Reference Circuit-B ............................................................................................. 20
Figure 13. RESET Timing Diagram ...................................................................................................................... 27
Figure 14. Switching Test Waveform.................................................................................................................... 27
Figure 15. Transceiver Impedance Limits ............................................................................................................ 31
Figure 16. Receiver Bias ...................................................................................................................................... 38
Figure 17. T7234 S/T Line Interface Scheme....................................................................................................... 42
Figure 18. T7903 S/T Line Interface Scheme....................................................................................................... 42
Figure 19. T7250C S/T Line Interface Scheme .................................................................................................... 43
Figure 20. T7903 to T7234 Direct-Connect Scheme............................................................................................ 44
Figure 21. T7250C to T7234 Direct-Connect Scheme ......................................................................................... 44
Figure 22. T7903 to T7234 Direct-Connect Scheme with External S/T-Interface ................................................ 45
Figure 23. T7250C to T7234 Direct-Connect Scheme with External S/T-Interface.............................................. 46
Tables
Table 1. Pin Descriptions........................................................................................................................................ 5
Table 2. U-Interface Bit Assignment ...................................................................................................................... 9
Table 3. Line Transmission Code......................................................................................................................... 13
Table 4. STLED States......................................................................................................................................... 15
Table 5. T7234 Reference Schematic Parts List .................................................................................................. 21
Table 6. Line-Side Resistor Requirements........................................................................................................... 23
Table 7. Power Consumption ............................................................................................................................... 25
Table 8. Digital dc Characteristics (Over Operating Ranges)............................................................................... 25
Table 9. S/T-Interface Receiver Common-Mode Rejection.................................................................................. 26
Table 10. Fundamental Mode Crystal Characteristics.......................................................................................... 26
Table 11. Internal PLL Characteristics ................................................................................................................. 26
Table 12. RESET Timing...................................................................................................................................... 27
Table 13. Power Dissipation Variation.................................................................................................................. 48
Table 14. Power Dissipation of CKOUT ............................................................................................................... 48
Table 15. Power Consumption ............................................................................................................................. 49
Table of Contents
T7234 Single-Chip NT1 (SCNT1) Euro-LITE Transceiver
(continued)
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