XRT83L38ES Exar, XRT83L38ES Datasheet - Page 37

• Manufacturer Part Number: XRT83L38ES
• Description: Peripheral Drivers & Components - PCIs
• Manufacturer: Exar

Specifications of XRT83L38ES

• Product Category: Peripheral Drivers & Components - PCIs
• Rohs: yes

REV. 1.0.2
TRANSMITTER (CHANNELS 0 - 7)
T
In Hardware mode, TXTSEL (Pin 84) can be tied “High” to select internal termination mode for all transmit
channels or tied “Low” for external termination. Individual channel control can be done only in Host mode. In
Host mode, bit 6 in the appropriate register for a given channel is set “High” to select the internal termination
mode for that specific transmit channel, see
page
In internal mode, no external resistors are used. An external capacitor of 0.68μF is used for proper operation of
the internal termination circuitry, see
E
By default the XRT83L38 is set for external termination mode at power up or at Hardware reset.
When external transmit termination mode is selected, the internal termination circuitry is disabled. The value of
the external resistors is chosen for a specific application according to the turns ratio selected by TRATIO (Pin
127) in Hardware mode or bit 0 in the appropriate register for a specific channel in Host mode, see
and
diagram for T1 (100Ω) in the external termination mode.
the external termination mode.
RANSMIT
XTERNAL
Table 22, “Microprocessor Register #3, Bit Description,” on page
51.
T
T
ERMINATION
RANSMIT
F
IGURE
OCTAL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
T
15. S
ERMINATION
M
TXTSEL
ODE
IMPLIFIED
0
1
X R T 8 3 L 3 8 L IU
TERSEL1
T
M
T
ABLE
0
0
1
1
ODE
ABLE
T R ING
Figure
D
R R IN G
T T IP
R T IP
IAGRAM FOR
8: T
9: T
13.
RANSMIT
Table 20, “Microprocessor Register #1, Bit Description,” on
ERMINATION
TX TERMINATION
TERSEL0
7 5
EXTERNAL
INTERNAL
E1
Ω
0
1
0
1
9 .1
9 .1
T
34
IN
ERMINATION
Ω
Ω
Figure 15
E
S
XTERNAL
ELECT
1 :2 .4 5
TERMINATION
1 :1
C
is a simplified block diagram for E1 (75Ω) in
C
ONTROL
T
100 Ω
110 Ω
120 Ω
ONTROL
75 Ω
ERMINATION
T
X
T
RANSFORMER
55.
1:2.45
Figure 14
1:2
75
75
M
ODE
Ω
Ω
R
(RXTSEL= 0)
ATIO
is a simplified block
XRT83L38
Table 10