CS61884-IB View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS61884-IB

Octal T1/E1/J1 Line Interface Unit

Cirrus Logic 

CS61884

18.1 Transformer specifications

Recommended transformer specifications are

shown in Table 12. Any transformer used with the

CS61884 should meet or exceed these specifica-

tions.

Table 12. Transformer Specifications

Descriptions

Turns Ratio Receive/Trans-

mit

Primary Inductance

Primary Leakage Induc-

tance

Secondary leakage Induc-

tance

Inter winding Capacitance

ET-Constant

Specifications

1:2

1.5mH min. @ 772 kHz

0.3 µH max @ 772 kHz

0.4 µH max @ 772 kHz

18pF max, primary to

secondary

16V - µs min.

18.2 Crystal Oscillator Specifications

When a reference clock signal is not available, a

CMOS crystal oscillator may be used as the refer-

ence clock signal. The oscillator must have a mini-

mum symmetry of 40-60% and minimum stability

of + 100ppm for both E1 and T1/J1 applications.

18.3 Designing for AT&T 62411

For information on requirements of the AT&T

62411 and the design of the appropriate system

synchronizer, refer to Application Note AN012

“AT&T 62411 Design Considerations - Jitter and

Synchronization” and Application Note AN011

“Jitter Testing Procedures for Compliance with

AT&T 62411”.

18.4 Line Protection

Secondary protection components can be added to

the line interface circuitry to provide lightning

surge and AC power-cross immunity. For addition-

al information on the different electrical safety

standards and specific applications circuit recom-

mendations, refer to Application Note AN034

“Secondary Line Protection for T1 and E1 Cards”.

DS485F1

53

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