ISL35111 Datasheet, PDF (6/8 Pages) Intersil Corporation – 11.1Gb/s Driver

ISL35111
CML Input and Output Buffers
The input and output buffers for the high-speed data
channel in the ISL35111 are implemented using CML.
Equivalent input and output circuits are shown in
Figures 6 and 7.
V_DD
IN[P]
2kΩO
50ΩO
IN[N]
10kOΩ
50ΩO
1^st LA
Stage
FIGURE 6. CML INPUT EQUIVALENT CIRCUIT FOR THE
ISL35111
V_DD
50ΩO
50ΩO
OUT[P]
OUT[N]
FIGURE 7. CML OUTPUT EQUIVALENT CIRCUIT FOR
THE ISL35111
Adjustable De-Emphasis
ISL35111 features a settable de-emphasis driver for
custom signal restoration.
The connectivity of the DE pins are used to determine the
boost de-emphasis level of ISL35111. Table 1 defines the
mapping from the 2-bit non-binary DE word to the 7
available output de-emphasis levels.
TABLE 1. MAPPING BETWEEN DE-EMPHASIS LEVEL
AND DE-PIN CONNECTIVITY
DE PIN
CONNECTION
DE[A] DE[B]
NOMINAL
DE-EMPHASIS LEVEL;
10.3125Gbps TO DE-EMPHASIS
11.1Gbps (dB)
SETTING
Open Open
0
0
Open GND
0.6
1
Open VDD
1.1
2
GND Open
1.6
3
GND
GND
2.3
4
GND
VDD
3
5
VDD Open
4
6
Disable Pin
The disable (TDSBL) pin is used to disable the driver
output in order to implement TX_Disable functions of
such industry standards as SFP+ and QSFP. When this
pin is pulled HIGH, the ISL35111 will enter a low-power
standby mode. For active data transmission, this pin
must be pulled LOW.
Line Silence/Quiescent Mode
The ISL35111 is capable of maintaining periods of line
silence by monitoring its input pins for loss of signal
(LOS) conditions and subsequently muting the output
driver when such a condition is detected. A reference
voltage applied to the detection threshold (DT) pin is
used to set the LOS threshold of the internal signal
detection circuitry. For most applications, it is
recommended to leave the DT pin floating at its default
internal bias. If the sensitivity of the detection threshold
needs to be adjusted, the DT voltage can be adjusted
with an external pull-up resistor. The resistor values
should be validated on an application-specific basis.
Connect the DT pin to ground in order to disable this
feature and prevent the outputs from muting during line
silence.
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airflow, and improves power consumption.
6
FN6975.0
November 19, 2009