5

FN6975.0

November 19, 2009

Operation

The ISL35111 is an advanced driver for high-speed

interconnects. A functional diagram of ISL35111 is

shown in Figure 5. In addition to a de-emphasis circuit to

compensate for FR4 channel loss and restore signal

fidelity, the ISL35111 contains unique integrated features

to preserve special signaling protocols typically broken by

other drivers. The signal detect function is used to mute

the channel output when the input signal falls below the

level determined by the Detection Threshold (DT) pin

voltage. This function is intended to preserve periods of

line silence.

As illustrated in Figure 5, the core of the high-speed

signal path in the ISL35111 is a sophisticated driver

followed by a de-emphasis circuit. The device applies

pre-distortion to compensate for skin loss, dielectric loss,

and impedance discontinuities in the transmission

channel.

FIGURE 3. ISL35111 10.3125Gbps OUTPUT; NO CHANNEL; PRBS-31

FIGURE 4. ISL35111 10.3125 GBPS OUTPUT AFTER A 22-INCH FR-408 TRACE, PRBS-31; DE-EMPHASIS 6

Performance is measured using the test setup illustrated in Figure 2. The signal from the pattern generator is launched

into the chip evaluation board. The ISL35111 output signal is then visualized on a scope to determine signal integrity

parameters such as jitter.

Signal

Detector

IN[P]

IN[N]

DT

LOS

OUT[N]

OUT[P]

Adjustable

De-Emphasis

Limiting

Amplifier

Output

Driver

Pre-

Driver

FIGURE 5. FUNCTIONAL BLOCK DIAGRAM OF THE ISL35111

ISL35111