XRT7302IQ80 View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT7302IQ80' PDF : 77 Pages View PDF
XRT7302 2 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
áç
REV. 1.1.0
Asia
150 Kampong Ampat
#07-01/02
KA Centre
Singapore 368324
Tel: 65-287-8998
FAX: 65-280-0080
3.0 THE RECEIVE SECTION
Figure 6 indicates that the Receive Section, within the
XRT7302 device consists of the following blocks:
• Attenuator/Equalizer
• Peak Detector
• Slicer
• Clock Recovery PLL
• Data Recovery
• HDB3/B3ZS Decoder
Each of these blocks will be discussed in some detail
below.
In general, the purpose of the "Receive Section” with-
in the XRT7302 device is to take an incoming attenu-
ated/distorted bipolar signal, from the line, and to en-
code it back into the TTL/CMOS format where it can
be received and processed by the Terminal Equip-
ment.
3.1 INTERFACING THE RECEIVE SECTIONS OF THE
XRT7302 DEVICE TO THE LINE
The design of the Receive Circuitry within the
XRT7302 device permits the user to transformer-cou-
ple or capacitive-couple the Receive Section to the
line. As mentioned earlier, the specification docu-
ments for E3, DS3, and STS-1 all specify 75 Ohm ter-
mination loads, when transmitting over coaxial ca-
ble. As a result, it is recommended to interface the
"Receive Section" of the XRT7302 device to the line
in a manner as shown in Figure 15 and Figure 16.
FIGURE 15. RECOMMENDED SCHEMATIC FOR INTERFACING THE RECEIVE SECTION OF THE XRT7302 DEVICE TO
THE LINE (TRANSFORMER-COUPLING)
RxPOS(n)
RxNEG(n)
RxClk(n)
RTIP(n)
Channel (n)
RPOS(n)
RNEG(n)
RxClk(n)
R1
37.5Ω
R2
37.5Ω
RRing(n)
Only One Channel Shown
C1
0.01uf
J1
T1
BNC
1:1
Receive Transformer Recommendations
PARAMETER
VALUE
Turns Ratio
1:1
Primary Inductance
40µH
Isolation Voltage
1500Vrms
Leakage Inductance
0.6µH
PART #
PE-68629
PE-65966
PE-65967
T3001
INSULATION
3000V
1500V
1500V
1500V
PACKAGE TYPE
Large Thru-Hole
Small Thru-Hole
Small, SMT
Small, SMT
38
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