xrt83l30 Exar Corporation, xrt83l30 Datasheet - Page 15

• Manufacturer Part Number: xrt83l30
• Description: Xrt83l30 -single-channel T1/e1/j1 Long-haul, Short-haul Line Interface Unit
• Manufacturer: Exar Corporation

TERMINATIONS
REV. 1.0.1
S
IGNAL
TERSEL1
TERSEL0
RXRES1
RXRES0
N
AME
SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
P
43
42
51
52
IN
#
T
YPE
I
I
Termination Impedance Select pin 1
Termination Impedance Select pin 0
In the Hardware mode and in the Internal Termination mode (TXTSEL=”1”
and/or RXTSEL=”1”) TERSEL[1:0] control the transmit and receive termina-
tion impedance according to the following table:
In the Internal Termination mode, the receive termination is realized com-
pletely by internal resistors or the combination of internal and one fixed exter-
nal resistor (see description for RXRES[1:0] pins). In the internal termination
mode the transformer ratio of 1:2 and 2:1 is required for the transmitter and
receiver respectively with the transmitter output AC coupled to the trans-
former.
N
Receive External Resistor Control pin 1
Receive External Resistor Control pin 0
In Hardware mode, RXRES[1:0] pins selects the required value of the exter-
nal fixed resistor for the receiver according to the following table. This mode
is only available in the internal impedance mode by pulling RXTSEL “High”.
N
OTE
OTE
: This pin is internally pulled "Low" with a 50kΩ resistor.
: Internally pulled “Low” with 50kΩ resistor.
RXRES1
12
0
0
1
1
TERSEL1
0
0
1
1
RXRES0
0
1
0
1
TERSEL0
D
ESCRIPTION
0
1
0
1
No External Fixed Resistor
RX Fixed Resistor
Termination
150Ω
240Ω
210Ω
100Ω
110
120Ω
75 Ω
Ω
XRT83L30