XRT5897 Datasheet, PDF (2/21 Pages) Exar Corporation – Seven-Channel E1 Line Interface

XRT5897
BLOCK DIAGRAM
1:2
TIP
RX INPUT
RING
RTIP7 (69)
R1
R2
RRING7 (68)
LOSCNT (73)
LOSSEL (38)
Tranceiver 1
Tranceiver 2
Tranceiver 3
Tranceiver 4
Tranceiver 5
Tranceiver 6
Tranceiver 7
Singnal
DPeteeacktor
RXPOS7 (5)
Receive
Comparators
RXNEG7 (6)
V_CC
LOS
Detect
Loss
Delay
1
MUX
O
LOS7 (4)
Counter
Transmit
Line
Drivers
TIP
2:1
R3
TTIP7 (89)
9.1
TX OUTPUT
RING
R4
TRING7 (91)
Pulse
Shaping
9.1
0
0
MUX
1
1
NRTRoZZ
CDyuctlye
Adjust
TXCLK7 (87)
TXPOS7 (85)
TXNEG7 (86)
Figure 1. XRT5897 Block Diagram
Receiver Notes
D The same type 1:2CT ratio transformer may be
used at the receiver input and transmitter output.
D R1 and R2 are both 150W for 75W operation, or
240W for 120W operation.
D Return loss exceeds ITU G.703 specification with
these resistors and a 1:2CT ratio input transformer.
LOS (Loss of Signal) Notes
D LOSSEL (pin 38) is connected to logic “1” for ITU
G.775 compliant LOS delay, or to logic 0 for user
programmable additional delay.
D LOSCNT (pin 73) is unconnected when LOSSEL is
logic 1, or connected to an external clock when
LOSSEL is logic 0.
Transmitter Notes
D Return loss exceeds ETSI 300 166 specification
with a 1:2 ratio transformer.
D R3 and R4 are always 9.1W for both 75W and 120W
applications.
D An approach exists that permits the user to operate
the XRT5897 with a 5V power supply. For more
information, please see application note TAN-12.
Rev. 1.11
2