ISL36111DRZ-T7 データシートの表示（PDF） - Renesas Electronics

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ISL36111DRZ-T7

11.1Gb/s Lane Extender

Renesas Electronics 

ISL36111

50Ω

VDD

50Ω

OUT [P]

OUT [N]

Internal LOS

Indicator

VDD

11k 

LOSB

FIGURE 6. CML OUTPUT EQUIVALENT CIRCUIT FOR THE

ISL36111

Line Silence/Quiescent Mode

Line silence is commonly broken by the limiting amplification in

other equalizers. This disruption can be detrimental in many

systems that rely on line silence as part of the protocol. The

ISL36111 contains special lane management capabilities to

detect and preserve periods of line silence while still providing

the fidelity-enhancing benefits of limiting amplification during

active data transmission. Line silence is detected by measuring

the amplitude of the input signal and comparing that to a

threshold set by the voltage at the DT pin. When the amplitude

falls below the threshold, the output driver stage is muted.

LOS Bar Indicator

Pin 4 (LOSB) is used to output the state of the muting circuitry to

serve as a loss of signal indicator for the device. This signal is

directly derived from the muting signal output by the detection

threshold / signal detector comparator. The LOSB signal goes

LOW when the signal detector output is below the externally

controlled detection threshold and HIGH when the detector

output goes above this threshold. This feature is meant to be

used in optical systems (e.g. SFP+) where there are no quiescent

or electrical-idle states. In these cases, the detection threshold is

used to determine the sensitivity of the LOSB indicator. Figure 7

shows the schematic of the LOSB equivalent output structure.

FIGURE 7. LOSB EQUIVALENT OUTPUT STRUCTURE

Detection Thereshold (DT) Pin

Functionality

The ISL36111 is capable of maintaining periods of line silence by

monitoring the channel 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. The DT voltage is set with an external pull-up

resistor, RDT. For typical applications, a 30k resistor is

recommended for channels with loss greater than 12dB at 5GHz,

and a 1.8k resistor is recommended for lower loss channels.

Other values of the resistor may also be applicable; therefore DT

settings should be verified on an application-specific basis.

FN6974 Rev 2.00

Jul 12, 2012

Page 6 of 9

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