User Manual

Table Of Contents
CS61880
52 DS450PP3
18.1 Transformer Specifications
Recommended transformer specifications are
shown in Table 15. Any transformer used with the
CS61880 should meet or exceed these specifica-
tions.
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 + 100 ppm.
18.3 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, Sec-
ondary Line Protection for T1 and E1 Cards.
Table 15. Transformer Specifications
Descriptions Specifications
Turns Ratio Receive 1:2
Turns Ratio Transmit 1:1.15
Primary Inductance 1.5 mH min @ 1024 kHz
Primary Leakage Induc-
tance
0.3 µH max @ 1024 kHz
Secondary leakage Induc-
tance
0.4 µH max @ 1024 kHz
Inter winding Capacitance 18 pF max, primary to
secondary
ET-Constant 16 V - µs min