CS61574A-IP1 View Datasheet(PDF) - Cirrus Logic

Part Name

Description

Manufacturer

CS61574A-IP1

T1/E1 Line Interface

Cirrus Logic 

CS61574A CS61575

Parameter

Turns Ratio

Receiver

1:2 CT ± 5%

Primary Inductance

Primary Leakage Inductance

Secondary Leakage Inductance

Interwinding Capacitance

ET-constant

600 µH min. @ 772 kHz

1.3 µH max. @ 772 kHz

0.4 µH max. @ 772 kHz

23 pF max.

16 V-µs min. for T1

12 V-µs min. for E1

Transmitter

1:1 ± 1.5 % for 75 Ω E1

1:1.15 ± 5 % for 100 Ω T1

1:1.26 ± 1.5 % for 120 Ω E1

1.5 mH min. @ 772 kHz

0.3 µH max. @ 772 kHz

0.4 µH max. @ 772 kHz

18 pF max.

16 V-µs min. for T1

12 V-µs min. for E1

Transformers

Table A2. Transformer Specifications

Designing for AT&T 62411

Recommended transmitter and receiver trans-

former specifications are shown in Table A2. The

transformers in Table A3 have been tested and

recommended for use with the CS61574A and

CS61575. Refer to the "Telecom Transformer Se-

lection Guide" for detailed schematics which

show how to connect the line interface IC with a

particular transformer.

In applications where it is advantageous to use a

single transmitter transformer for 75Ω and 120Ω

E1 applications, a 1:1.26 transformer may be

used. Although transmitter return loss will be re-

duced for 75Ω applications, the pulse amplitude

will be correct across a 75Ω load.

Selecting an Oscillator Crystal

Specific crystal parameters are required for

proper operation of the jitter attenuator. It is rec-

ommended that the Crystal Semiconductor

CXT6176 crystal be used for T1 applications and

the CXT8192 crystal be used for E1 applications.

For additional information on the requirements of

AT&T 62411 and the design of an appropriate

system synchronizer, please refer to the Crystal

Semiconductor Application Notes: "AT&T 62411

Design Considerations – Jitter and Synchroniza-

tion" and "Jitter Testing Procedures for

Compliance with AT&T 62411".

Transmit Side Jitter Attenuation

In some applications it is desirable to attenuate

jitter from the signal to be transmitted. A

CS61575 in local loopback mode can be used as a

jitter attenuator. The inputs to the jitter attenuator

are TPOS, TNEG, TCLK. The outputs from the

jitter attenuator are RPOS, RNEG and RCLK.

Line Protection

Secondary protection components can be added

to provide lightning surge and AC power-cross

immunity. Refer to the application note "Secon-

dary Line Protection for T1 and E1 Line Cards"

for detailed information on the different electrical

safety standards and specific application circuit

recommendations.

30

DS154F2

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